Trichoderma is a naturally occurring genus of soil fungi which has been known to possess bio control qualities against a number of plant pathogens since the 1920s. While there are a number of plant-associated microbes, both fungi and bacteria which are strongly beneficial to plants, none has been more intensively studied than Trichoderma. Stable and effective preparations of Trichoderma have also been formulated into a range of bio control or “effective microorganism” products readily available on the market for both large-scale commercial producers and smaller home gardeners. Although Trichoderma is naturally endemic to soil and decomposing organic matter, it is well proven to have significant beneficial effects in soilless systems and formulations have been developed specifically for hydroponic use. While Trichoderma can be highly effective as both a pathogen control agent and growth promotant, it is a living organism and as such requires specific conditions for establishment and long term use within a hydroponic system.

How does Trichoderma operate?

Many species of Trichoderma, if given optimal conditions, establish stable and long-lasting colonisations of root surfaces and even penetrate into the epidermis (outer layer of root tissue) and a few cells below this level ⁽¹⁾. This intimate relationship between Trichoderma and the host root cells is what induces localized and systemic resistance responses to pathogen attack. Along with root penetration, Trichoderma produces a range of antibiotic substances, can strongly compete with other micro organisms for food, and produce enzymes that can degrade cellulose and chitin. Trichoderma also has the ability to dissolve the cell wall membranes of pathogenic fungi.

Initially Trichoderma species were only thought to have suppressive effects on a small number of plant root pathogens, however as research into the methods of this suppressive effect were studied, it was found that Trichoderma had other beneficial properties on plant growth and development. These growth enhancement effects went further than just suppression of pathogen in the root zone allowing a return to normal healthy growth. It has been found that the species Trichoderma spp. increase the uptake and concentration of a variety of nutrients (copper, phosphorus, iron, manganese and sodium) in the roots in hydroponic culture ⁽³⁾. This increased uptake suggests Trichoderma creates an improvement in plant active-uptake mechanisms as well as having been shown to increase root development in numerous plant species. The beneficial effects of Trichoderma on plant growth overall has been indicated to be from a combination of reducing damage, even non-visible damage, from plant pathogens, deactivation of toxic compounds in the root zone, increases in nutrient uptake, efficiency of nitrogen use and solubilization of nutrients in soil and organic matter. It is possible Trichoderma species release certain molecular elicitors of plant growth promotion in a similar way that growth promotion by certain bacteria is known to occur, however this is still an area of ongoing research and such compounds are as yet unidentified ⁽¹⁾

Trichoderma and disease control

Trichoderma is not just one species of fungi – the genus Trichoderma contains many species and strains, of which some are specific to certain pathogenic fungi such as Pythium and Rhizoctonia. For example, T. virens has been found to be specific to certain fungal diseases of field grown cotton, while T. asperellum has been found to protect cucumber leaves from Pseudomonas syringae when only applied to the root system demonstrating that some Trichoderma strains have systemic abilities. Of all the Trichoderma species, T. harzianum, of which there are several strains, is the most widely commercialised and has been found in scientific studies to be effective against a range of fungal plant pathogens, including Botrytis, Colletotrichum, Green-mottle mosaic virus, Alternaria solani, Pythium sp., Phytophthora capsici, Rhizoctonia, Fusarium,Sclerotinia ⁽⁴⁾ and

One of the most effective methods of pathogenic fungal control exhibited by Trichoderma is `mycoparasitism’. In this process the Trichoderma first detect other target fungi species and grow towards them, once contact is made, the Trichoderma attach and coil around the fungus, then produce several fungitoxic cell-wall degrading enzymes and probably also certain antibiotic compounds. These two activities results in dissolution of the fungal cell walls and parasitism of the target fungus. ⁽¹⁾

Another highly effective mechanism of control by Trichoderma is the ability of certain strains to induce phytoalexin defence compounds in plants and seedlings. Phytoalexins are the plant’s own natural defense system for fighting off attack by pathogens and although induced resistance systems in plants are complex, they are often highly effective strategies for disease control. The exact nature of resistance system triggering molecules from the Trichoderma response are unknown. However it has been proven that applying certain Trichoderma strains to the root zone of hydroponically grown plants has given control of certain leaf pathogens (i.e. systemic control) and it is this inducement of the plant’s natural defense system by Trichoderma that is likely to be responsible for this effect.  Therefore Trichoderma has two important modes to action – direct suppression of the pathogen with production of antibiotic substances and enzymes and strongly stimulating the plant’s own natural defense mechanism.

Why do growers love Trichoderma so much?

Apart from pathogen suppression and growth promotant activities, Trichoderma has been selected for widespread use in horticulture for a number of other reasons. The spores of Trichoderma can be easily formulated into long shelf life products that, upon reactivation, rapidly colonize the growing media under suitable conditions. Trichoderma is a strong competitor in the root zone and generally has a good chance of establishment even when there are pre-existing healthy populations of other microbial species. Trichoderma has also proven to be compatible with a number of other bio control agents, including beneficial fungi in a number of different studies, so that mixtures of effective microbes can be safely applied. Trichoderma spp. In general have also been found to be highly resistant to a variety of toxins including chemical fungicides, heavy metals and antibiotics produced by other microbes ⁽¹⁾ . While Trichoderma is commonly applied to the root zone or nutrient solution, certain strains have also been applied to fruit, flowers and foliage to control certain plant pathogens and even used to prevent post harvest rot disease. One study found that application of Trichoderma spp. on greenhouse strawberries could control post harvest rotting, while several Trichoderma spp. have been used to protect fruit such as banana, apple, mango and tomato during post harvest storage ⁽⁴⁾. There is evidence to suggest Trichoderma assists plant growth and development under `stressful’ conditions and the growth promotant potential of Trichoderma appears to be stronger in crops growing under less than ideal conditions.

How to get Trichoderma established in hydroponics

Trichoderma is best used as a preventative and since it may take time for complete colonisation of growing substrates, inoculation should be carried out as early in the crop’s life as possible. A warm, moist growing media, thoroughly inoculated with Trichoderma will rapidly be colonised, and some additional inoculate can then be added directly under the root system of the young transplant. Soaking the root system of transplants or cuttings with Trichoderma inoculate can also be helpful to ensure high levels of the microbial product are applied in the right position. While Trichoderma should take hold rapidly and colonise the entire growing media, over time the population may decline and fresh inoculation throughout the growing cycle are recommended.  Since many pathogens such as Pythium which causes `damping off’ in seedlings are more prevalent during the sensitive propagation phase, inoculation of seed germination media with Trichoderma is particularly important.  Trichoderma has also been shown to increase the germination percentage of tomato seeds sown in soilless growing media when Pythium pathogens were present ⁽⁵⁾ . Cuttings or clones also benefit from Trichoderma application as a preventive for stem rot pathogens and to ensure the new root system is fully colonized and protected by Trichoderma before potting on or introducing to a new hydroponic system. Since Trichoderma is a living organism, commercially available inoculant products tend to have a limited shelf life, so it is advisable to always check the expiry date and follow usage and storage instructions provided with the product.

What substrates are best for Trichoderma establishment

Hydroponic systems are generally not sterile environments, however they do tend to contain lower levels and less diversity of micro-organisms compared to soil. Before planting out, sterile growing media, clean and disinfected equipment and a treated water supply provides a clean slate for microbial establishment.  For this reason it is considered easier to establish beneficial microbes in hydroponic systems with a new substrate as little competition exists from micro-organism already present, unlike the situation in soil ⁽⁶⁾. If the system is using synthetic growing media such as rockwool, rather than composted bark, coco fiber or similar substrates, then initially the system is a relatively poor environment for microbial life to take hold and microbe numbers and population diversity have been found to be very low. However once the plants are growing, exudates from the roots and sloughed off root material begin to provide organic substances for microorganisms to grow and population numbers build over time. A substantial part of the food source used by micro flora is derived from plant roots, resulting in high numbers of micro organisms on the surface of plant roots consuming organic compounds such as carbohydrates, mucilage and dead cell material which accumulates over time.

While Trichoderma has been shown to establish and proliferate on a range of soilless substrates, there is some evidence that colonization may be greater on certain growing mediums. When coconut fibre (Coir) and rockwool were compared after inoculation with T. harzianum it was found that colonization was greater in the coco fiber, with spread through the rockwool substrate being less dense. It was also found that colonization of Trichoderma was highest at the site of inoculation suggesting that the initial introduction of Trichoderma into a growing medium should be at multiple sites or well mixed through the substrate before planting ⁽⁷⁾ .

Oxygen and temperature

Trichoderma, like many microbial species has temperature optimums for rapid colonization and activity, for most of the commonly applied species this is 77-86 F (25-30^o C) ⁽⁸⁾. If conditions are too cold, the rate of multiplication of the Trichoderma will slow and even cease, if too warm, then die back may occur or the Trichoderma may become out competed, leaving the way open for other forms of microbial species to take hold.

Another important consideration is oxygen in the root zone – Trichoderma and other microbial species require oxygen for healthy functioning and unfortunately oxygen starvation is a common cause of root disease outbreaks in many hydroponic systems. Over watering with either too frequent application of nutrient solution, stagnation and deep ponding in NFT systems, heavy water logged growing media with poor drainage all lead to a lack of oxygen in the root zone which suffocates both root systems and Trichoderma. If the root system then becomes damaged due to over watering and a lack of oxygen, this combined with the die back of Trichoderma and other beneficial microbes create the ideal situation for opportunist root pathogens such as Pythium to take hold.

High levels of oxygenation in the hydroponic root system are relatively easy to maintain with selection of the correct type of growing media for the conditions (coarser and freer draining when it’s cooler and growth slower is always advisable to help prevent over watering). Careful control over nutrient application to allow thorough drainage between irrigations which helps draw fresh air through the substrate and replenish oxygen and a nutrient which as some opportunity to re-oxygenate in recirculating systems.

Trichoderma variability and limitations

While Trichoderma has proven to be effective for pathogen control in a wide range of applications, results can sometimes be variable when dealing with biological control systems.  Control is dependant on the Trichoderma being applied at the correct time (i.e. before levels of pathogens have built to high levels), under the correct conditions of moisture and temperature and of an effective species and strain. Poor control by bio control agents is also attributed to poor distribution in the root zone and growing media and location – Trichoderma introduced at a different location to where the pathogen is residing. Initial introductions of Trichoderma can be beneficial if applied directly to or under the root system of new transplants as it is likely that any pathogens such as Pythium will be introduced to a clean system via infected seedlings. Another limitation is that Trichoderma is more specific to fungal pathogen control and may have limited applications for bio control of pathogenic bacteria ⁽⁴⁾ , some of which can cause serious disease outbreaks.

While Trichoderma is a popular fungal bio control agent, there are also a number of bacterial `effective microbe (EM)’ species (bacteria in the genera Pseudomonas, Bacillus and Streptomyces) which can also be introduced to the root zone of plants. Often, for unknown reasons, Trichoderma may not persist in the root zone long term, thus protection can decline as the crop develops. Re application of Trichoderma products on a regular basis is always recommended to ensure population levels don’t die out resulting in a lack of pathogen protection in the root zone.

Trichoderma compatibility with other beneficial fungi species

Trichoderma are not the only fungi with beneficial effects on plant growth and disease suppression. While there are a vast number of fungal species which may have benefits for crop production, only a small number have been identified and studied. Of these the arbuscular mycorrhizal fungi, Gliocladium virens, non pathogenic F. oxysporum, Paecilomyces lilacinus, Penicillium chrysogenum, and a number of others have been identified in studies as having an antagonistic effect on pathogenic fungi. In many of these studies it has been discovered that combinations of synergistic fungi species often have a greater effect on disease control than when used singly ⁽⁹⁾.

Trichoderma compatibility with Mycorrhizal fungi

Arbuscular mycorrhizal (AMF) fungi are another wide spread, naturally occurring soil micro organism which forms a beneficial relationship with the roots of many plant species. Just as with Trichoderma species, enhanced growth and disease suppression has been well documented with the use of mycorrhizal fungi inoculated in the root zone of cropping plants ⁽¹⁵⁾ . Given that Trichoderma is such a strong predator and competitor of other species of fungi in the root zone, there has been concern in the past that negative interactions between Trichoderma and mycorrhizal inoculants could occur, thus making one or both fungi inactive and therefore incompatible. While numerous scientific studies have been carried out to determine if Trichoderma verses mycorrhizal antagonism does exist when both are introduced to the root zone of certain plant species, conflicting results have been reported.

The problem identifying if this sort of interaction does occur is that in biological systems there are multiple factors affecting the result. Not only are there many species of Trichoderma with different characteristics and abilities to predate other fungi, but mycorrhizal fungi also contain a number of species including Glomus claroideum, Glomus mosseae, Glomus intraradicesGlomus geosporum. Furthermore the conditions in which the fungi are introduced, the crop species tested, growing media, presence of other microbial life and a host of other factors affect the result of fungal interactions. While one study (Green et al, 1999) found that the Mycorrhizal fungi G. intraradices had an averse effect on Trichoderma harzianum, yet another study (Martinez-Medina et al, 2009) reported that combined inoculation with these two species provided better disease control results and a general synergistic effect than other Mycorrhizal species tested. and

Many other studies have found a synergist effect when Trichoderma was use in combination with certain species of Mycorrhizal fungi. It has been reported that dual inoculation of peat substrate with a mixture of 4 species of Mycorrhizal fungi and Trichoderma harzianum showed a significant effect on the growth and flowering of cyclamen plants ⁽¹²⁾, while another study found that more plant biomass was produced in a peat-perlite mixture when the mycorrhizal fungus Glomus mosseaeTrichoderma aureoviridae ⁽¹³⁾ . Other researchers have also reported that various microbial inoculants such as Trichoderma and others showed no negative effects on Mycorrhizal establishment ⁽¹⁴⁾, while others have reported that combinations of Mycorrhizal fungi species with Trichoderma harzianum and other beneficial fungi have a synergistic effect and give greater increases in growth and disease resistance when combined ^{(15, 16, 17)} . It has been suggested that the differing results reporting the influence of Mycorrhizal fungi on other micro organisms is probably not only due to the combination and species of Mycorrhizal fungi evaluated but also the conditions such as nutrient availability when the studies were carried out ⁽²⁰⁾ . was combined with

The bulk of the scientific evidence suggests however that the species of Trichoderma and Mycorrhiza commonly used as inoculants in soil and hydroponics are compatible and potentially synergistic when used in combination. Trichoderma and Mycorrhiza carry out different but potentially very beneficial roles in the root zone of plants, involving not only protection from many pathogens, but also nutritional and growth benefits.

Trichoderma Q&A

What do Trichoderma use as a food source?

Trichoderma release two main types of enzymes in their quest for sustenance – these are different types of cellulases and chitinases. Cellulase enzymes break down cellulose which is a component of plant cells, organic matter and crop residues. Chitinase breaks down Chitin which is a structural component of fungal cell walls (and insect exoskeletons). It is thought that Trichoderma switches the production of these two main enzymes on and off depending on what its main source of food is at the current time. In composts, bark, coconut fiber and other `organic’ type substrates there is initially plenty of cellulose to feed on, later on in the crop cycle, plant residues, exudates, dead roots and other organic material are also available for the Trichoderma to digest. Other fungi (certain species of Trichoderma are specific for certain fungi, while others have a wider range of prey) are a easily digested food source through activation of chitinase enzymes and the Trichoderma will actually coil around the host fungi and penetrate the cell walls fairly rapidly

Will Trichoderma survive in the absence of other fungi to feed from and if so what do they feed on particularly in a hydroponic environment?

Trichoderma not only feed on other fungi, but also on cellulose from various sources of organic matter. We sometimes assume that hydroponic systems are completely `clean’, and non-organic and not capable of supporting a diversity of microbial life, but this is rarely the case. Even systems such as rockwool which start out as completely sterile, rapidly develop some forms of microbial life as the warmth, moisture, nutrients and organic matter produced by the plant’s root system provide a good environment for microbes. In fact, in hydroponics where there is typically year around heat, plentiful moisture, oxygen and rapid plant growth, microbial growth can be quite plentiful provided the grower is not doing something incompatible such as applying harsh chemical sterilants such as chlorine or hydrogen peroxide to the plants root zone or nutrient solution. Even in solution culture microbial life in the nutrient develops – hopefully the `good’ microbes out compete any pathogens and a well oxygenation solution helps with that process. In these cases the food source, if not other fungi, will be organic matter provided by either the substrate or the plant’s root system which produce exudates, old root cells which are sloughed off as the root system expands and other debris.

What do Trichoderma get from root invasion?

Trichoderma penetrate into the cells of the root system – once this occurs, it triggers a response in the plant host which effectively `walls off’ the Trichoderma and prevents it getting any further into the living root tissue. In triggering this response, the plants natural system of defence is activated and a systemic resistance is induced.  This relationship between Trichoderma and plant roots is termed an `opportunistic avirulent symbiotic relationship’ meaning even though the Trichoderma has gained entry to the plant tissue, it does not cause any disease or damage. Symbiotic means both parties benefit, the plant gets protection and the Trichoderma gets a good place to live and also some plant derived sucrose which is an important resource provided to the Trichoderma cells in this association ⁽²²⁾.

How do Trichoderma attack and control pathogens?

Many Trichoderma species are specific for certain pathogens and will predate these if they are present in the same location – this is through a number of different processes. The main method of attack is for the Trichoderma to coil around the pathogenic fungi, release enzymes to break down the cells and consume its prey. It is thought Trichoderma also release a number of antibiotic compounds for direct control. Another method of pathogen control is through inducing systemic resistance in the host plant, Trichoderma does this by invading the plant’s root system to the depth of a few cells, which triggers the plant to launch its natural defence mechanism to wall off the Trichoderma, in doing so the systemic resistance spreads through the entire plant so that foliar and fruit diseases may be controlled as well.

How can Trichoderma products be reactivated and are there any compounds that can be used to help feed or promote Trichoderma.

Generally the manufacturer’s instructions should always be carefully followed when reactivating the spores contained in a commercial Trichoderma product as there are a number of different preparations and additives or `carrier agents’ used. Some are granules or powers designed to be incorporated directly into growing media, some as a liquid drench. Trichoderma prefers warmth, moisture and oxygen for reactivation, once that occurs a readily available food source is also helpful for rapid development. There has been some evidence that using a growing medium such as composted bark fines, coconut fiber or small volumes of compost/vermicast additions gives faster establishment as it provides a cellulose food source for the Trichoderma in the early stages when the plant root system is still small. However, with hydroponics it’s essential to not overload the nutrient solution and system with large volumes of organic matter or additives – in doing so the rapid explosion in many forms of microbial life can rob all oxygen from the root zone creating a situation where roots are suffocated and pathogens flourish under anaerobic conditions.

Are there upper limits of nutrient solution concentration that Trichoderma can tolerate? Will they survive in high EC solutions and/or do better in low EC solutions?

The range of EC typically used in hydroponics, is actually quite narrow compared to the salinity levels in some soils and the rise in osmotic potential that occurs as soil dries out, so Trichoderma is unlikely to be affected by hydroponic EC levels. Trichoderma `eat’ organic matter cellulose and chitin from fungi cells, so unless for some reason the EC is affecting these sources of food, it should have no real influence on the Trichoderma itself. Trichoderma is known to survive and thrive in a diverse range of environments in the presence of toxins, heavy metals and certain chemicals, so EC is unlikely to have any significant effects. Even EC levels high enough to stunt and damage plant growth should have no influence on Trichoderma.

Why does Trichoderma give greater growth potential to plants growing under stressful conditions?

Largely because there is more potential for growth improvement under less than ideal growing conditions than with plants already at maximum biomass production – the effect is thought to be a combination of both suppression of pathogens, many of which are opportunistic and will attack stressed plants, and by possible production of certain elicitors of plant growth which are as yet unidentified.

Does coir naturally contain Trichoderma, even after the coir treatment process?

This depends largely on the processes used in the different brands of coir. Some coir is heat treated to kill seeds, insects and pathogen spores, and in this case any naturally occurring Trichoderma will also have been destroyed. Some coir products and other growing mixes on the market are deliberately inoculated with Trichoderma before sale. Coir is typically retted and then composted during its manufacture as a plant growth medium, so during this process it’s likely that Trichoderma colonise the fibres and break down some of the cellulose, however that would depend on a number of factors such as the location, if the coir piles are covered or in contact with the soil, the populations of other microbes in the surrounding environment and other factors. Many studies have found naturally occurring Trichoderma (and other beneficial fungi species as well) in a range of coir substrates and it has also been found in some studies that these microbes had disease suppressive qualities ⁽²¹⁾.

By Dr Lynette Morgan

References and Sources of information

1. Harmen G E, Howell C R, Viterbo A, Chet I and Lorito M., 2004. Trichoderma species – opportunistic, avirulent plant symbionts. Nature Reviews Microbiology Vol.2 pp43-56.

2. Harmen G E., 2006. Overview of mechanisms and uses of Trichoderma spp. Phytopathology Vol. 96(2) pp 190-194.

3. Yedidia I, Srivastva A K, Kapulnik Y and Chet I., 2001. Effect of Trichoderma harzianum on micro element concentrations and increased growth of cucumber plants. Plant and Soil Vol.235 pp 235-242,

4. Verma M, Mrar S K, Tyagi R D, Surampalli R Y and Valero J R., 2007. Antagonistic fungi, Trichoderma spp,: Panoply of biological control. Biochemial Engineering Journal Vol.37 pp1-20.

5. Aerts R, De Schutter B and Rombouts L., 2002. Suppression of Pythium Spp. by Trichoderma spp. during germination of tomato seeds in soilless growing media. Meded Riijsuniv Gent Fak Landbouwkd Toegep Bio Wet. Vol.67(2) pp 343-351.

6. Postma J, van Os E and Bonants E J M., 2008. Pathogen detection and management strategies in soilless plant growing systems. In: Soilless Culture theory and practice, Elsevier. London UK.

7. De Schutter B, Aerts R and Rombouts L., 2001. Colonisation of soilless growing media for tomato by Trichoderma harzianum. Meded Riijksuniv Gent Fak Landbouwkd Biol Wet. Vol. 66(2a) pp205-212.

8. Mukherjee P K and Raghu K., 1997. Effectof temperature on antagonistic and biocontrol potential of Trichoderma sp. On Sclerotium rolfsii. Mycopathologia Vol.139, pp151-155.

9. Siddiqui Z A and Akhtar M S., 2008. Synergist effects of antagonisitc fungi and a plant growth promoting rhizobacterium, an arbuscular mycorrhizal fungus, or composted cow manure on populations of Meloidogyne incognita and growth of tomato. Biocontrol Science and Technology Vol. 18(3) pp 279-290.

10. Green H, Larsen J, Olsson P A, Jensen D F,and Jakobsen I., 1999. Suppression of the Biocontrol agent Trichoderma harzianum by Mycelium of the arbuscular mycorrhizal fungus Glomus intraradices in root-free soil. Applied and Environmental Microbiology Vol.65(4) pp1428-1434.

11. Martinex-Medina A , Pascual J A, Lloret E and Roldan A., 2009. Interactions bewteen arbuscular mycorrhizal fungi and Trichoderma harzianum and their effects on Fusarium wilt in melon plants grown in seedling nurseries. Journal of the Science of Food and Agriculture Vol.89 (11) pp1843-1850.

12. Dubsky M, Sramek F and Vosatka M., 2002. Inoculation of cyclamen and pointsettia with arbuscular mycorrhizal fungi and Trichoderma harzianum. Rostlinna Vyroba Vol.48(2) pp63-68.

13. Calvet C, Pera J ande Barea J M., 1993. Growth response of Marigold to inoculation with Glomus mosseae, Trichoderma aureoviride and Pythium ultiumum in a peat-perlite mixture. Plant and Soil Vol.148 pp1-6.

14. Mar Vazquez M M, Cesar S, Azcon R and Barea J M., 2000. Interactions between arbuscular mycorrhizal fungi and other microbial inoculants (Azospirillum, Pseudomonas, Trichoderma) and their effects on microbial population and enzyme activities in the rhizosphere of maize plants. Applied Soil Ecology Vol.15(3) pp261-272.

15. Srinath J, Bagyaraj D J and Satyanarayana B N., 2003. Enhanced growth and nutrition of micropropagated Ficus benjamina to Glomus mosseae co-inoculated with Trichoderma harzianum and Bacillus coagulans. World Journal of Microbiology and Biotechnology Vol.19 pp69-72.

16. Srivastava R, Khalid A, Singh US and Sharma A K., 2010. Evalution of arbuscular mycorrhizal fungus, fluorescent Pseudomonas and Trichoderma harzianum formulation against Fusarium oxysporum F. sp. Lycopersici for the management of tomato wilt. Biological Control Vol. 53(1) pp24-31.

17. Waechter-Kristensen B, Gertsson U E and Sundin P., 1994. Prospects for microbial stabilisation in the hydroponic culture of tomato using circulating nutrient solution. Acta Horticulturae vol 361.

18. Gravel V, Martinex C, Antoun H and Tweddell., 2006. Control of tomato root rot (Pythium ultimum) in hydroponic systems using plant-growth-promoting mico organisms. Canadian Journal of Plant Pathology. Vol.28 pp 475-483.

19. Monte E., 2001. Understanding Trichoderma: between biotechnology and microbial ecology. Int. Microbiology Vol. 4 pp 1-4.

20. Hodge A., 2000. Microbial ecology of the arbuscular mycorrhiza. FEMS Microbiology Ecology, Vol.32(2) pp 91-96.

21. Hyder N, Sims, J J and Wegula S N., 2009. In vitro suppression of soilbourne plant pathogens by coir. HortTechnology Vol. 19(1) pp96-100

22. Vargas W A, Mandawe J C, Kenerley C M., 2009. Plant-derived sucrose is a key element in the symbiotic association between Trichoderma and Maize plants. Plant Physiology Vol. 151(2) pp792-808.

A greenhouse designed and manufacturered by Rimol

A New Hampshire greenhouse manufacturer and a California hydroponics company are hoping that their budding East/West relationship will be one that bears fruit for their customers and the environment.

Hooksett, NH-based Rimol Greenhouse Systems (RGS) and Arcata, California-based American Hydroponics (AmHydro) announced today that they have entered a partnership for the mutual goal of providing growers with exceptional value and service in total design and implementation of greenhouses and hydroponic systems.

“Given the unprecedented rise of the hydroponics industry and the fact that more and more people are recognizing the benefits of locally grown food, this partnership makes sense on so many different levels,” said Rimol Greenhouse Systems Founder Bob Rimol. “As industry leaders in our individual disciplines, we understand that by partnering, we can offer our customers the best possible blueprint and game plan to grow healthier and safer food for themselves and their neighbors.”

Hydroponic plant cultivation is an efficient method of achieving maximum production in minimal space, without soil, by recirculating minerals dissolved in water. As an established branch of horticulture, hydroponics uses 1/10th the amount of water as a regular farm to produce the same amount of food. When coupled with greenhouses, no harmful pesticides or herbicides are required ensuring optimum plant and human health.

RGS designs, manufactures and installs greenhouse structures and systems that control light, temperature (heating and cooling), CO2 and the overall environment. Even insect control is factored into the overall greenhouse design, which also takes into account the best crops to grow, budget and revenue expectations.

Located in a 16,000-square-foot manufacturing facility overlooking the foothills, green pastures and tall redwoods in Humboldt County, California, American Hydroponics has been providing state-of-the-art crop performance products and services for people to grow crops successfully for the past 26 years. American Hydroponics currently has the highest rate of successful growers using their commercial hydroponic systems than any other system manufacturer and looks forward to combining their skills and expertise with their new partner.

“RGS shares our belief that the well-being of the environment is everyone’s responsibility and that water and land conservation is more important than ever before,” said American Hydroponics President Michael Christian. “Recognizing the fact that a smarter approach to farming has become a necessity to preserve farmland and other natural resources, the synergy between our two companies is natural and the relationship extremely beneficial to our customers.”

One company that has already benefited from the partnership is Hackettstown, New Jersey-based Greenway Flowers, which has expanded their traditional floral business to also include hydroponic, food-producing greenhouses. With a new, state-of-the-art RGS greenhouse outfitted with an American Hydroponics lettuce growing system, Greenway is now diversifying their business and finding a new revenue stream.

“Today Mom and Pop florists have to compete against supermarkets, online companies and imported flowers. In order to ensure our long-term sustainability as a business, we needed to branch out and add something new,” said Greenway Flowers Owner George Cummings. “With the greenhouse and lettuce growing systems, we have a new product, new customers and enhanced cash flow. Now, instead of just being florists, we’re also learning to farm.”

To learn more about RGS, visit www.rimolgreenhouses.com. To learn about the benefits of an American Hydroponics system, visit www.AmericanHydroponics.com.

Of all the hydroponic growing media you can use water is cheap and the easiest to obtain. Water can be filtered, typically with an RO machine, and sterilized with UV or Ozone to create a clean and consistent substrate tailored to your growing requirements. Many hydroponic growers already understand the virtues of using, and more importantly reusing, water in hydroponic systems. So, why not go the whole hog, throw away your rock wool/soil/coco/clay pebbles and use water culture?!

What is Water Culture?

Deep water culture (DWC) – At its essence, a DWC system is made up of a container, lid and net pot. The container holds the nutrient solution (typically 2.5–4 gallons (10–15 liters)) and the lid supports a single plant growing in a net pot. Roots grow out the net pot and into the nutrient solution held in the container below. In the container, an air stone bubbles away to agitate the solution and keep dissolved oxygen levels high—essential in any DWC system. Shallow water culture (SWC) is based on the same principle but, yes you’ve guessed it, uses a lower volume of water.

Single vs. Recirculating

Single stand-alone systems are fairly cheap to buy and even more popular for DIY enthusiasts. Modular DWC systems, in which many containers are connected to a central reservoir, create an active system where the nutrient solution is able to cycle from the reservoir around all the pots, arriving back at the reservoir. Each has inherent issues. Stand-alone systems can be inconvenient to work with, while recirculating systems can spread problematic root diseases very quickly. The key is to operate the chosen water culture system properly, and you’ll be sure to get explosive results. Once you play around with DWC, you’ll most likely wish your system was modular and recirculating.

Q: Ok, lets start with the basics; what types of nutrients and additives work in DWC?

A: In my experience, pure synthetics of the highest solubility tend to work best. Especially formulations with well-balanced mineral ratios as well as being balanced on a molecular level. This tends to translate to a more pH stable nutrient solution that stays viable for longer periods of time.

Q: Where do you stand when it comes to Beneficial Biology in DWC systems?

A: There’s a bit of a fork in the road philosophically when it comes to“bennies” or no “bennies”. In my experiences both tend to work but I lean towards more of a sterile aqueous root zone. It is possible to use a more carbon-based substrate for a plant’s root crown cultivation. It’s this beneficial habitat that could harbor and allow colonization of a plant’s mutualistic organisms. The solution itself has little potential for colonization of anything other than bacteria, which while useful, don’t offer the benefits of fungi’s, which share a more direct relationship with the roots themselves.

Q: Are there any specific pH and EC requirements you recommend?

A: Depending on the nutrient, working with a pH between 5.5–6.5 works fine. If you want to be more specific 6.0–6.3 for veg, and 5.7–5.9 for flower. It’s in these pH ranges that the minerals most needed for the respective plant cycles are most available. With regards to EC, I generally recommend 50–75% of a nutrient manufacturers directed dosage for best results. Remember that lower EC can result in a higher intake of water into a plant’s tissue, which in turn speeds plant metabolism and increases nutrient transport.

Q: How often should growers change-out the nutrient solution? Are there signs they should look out for?

A: Depending on the type of nutrients, a 14–21 day change out schedule is typical. When plants are growing vigorously they can turn the nutrients over several times in that time frame. This is essentially “changing the nutes” by displacement from the top-off reservoir. If the nutes begin to fluctuate in pH or become murky, or if plants begin reducing nutrient usage this is usually a good time to purge the reservoir and mix a fresh batch.

Q: What is the ideal water temperature for DWC systems?

A: We’ve observed that no matter the ambient air temperature, plant roots tend to do best at 62–68°F (17–20°C). Above 72°F (21°C) the solutions dissolved oxygen (DO) holding potential quickly diminishes and below 60°F (16°C) plants tend to slow their metabolism in response to what is perceived as changing seasons. This said, growers could aid in fruit/flower ripening by reducing water temps toward the end of the reproductive cycle. Being able to dial in each zone of the plant (Leaf/Root) specifically often leads to an amplification of plant productivity.

Q: Speaking about DO, what is the best practice for monitoring and maintaining DO levels?

A: Keep nutrients cool and ppm’s at a modest level to ensure good DO saturation. Surface aeration and the implementation of air pumps and diffusers is an easy way to keep the solution agitated and moving. Manual as well as digital meters can be useful for those more meticulous souls. If you go digital buy high end as the budget meters (which still run several hundred dollars) are typically unreliable instruments in a pretty plastic housing.

Q: Can you run through your recommendations for propagating plants destined for DWC?

A: Establishing cuttings with an aeroponic cloner using 1/8th strength nutrients is ideal, preferably under mixed spectrum T-5 lighting. Propagating bare root plants suits DWC best. This offers an easier transition to water culture given there is no wicking substrate (rock wool, Sure To Grow) to hold excess moisture too close to the root crown.

Q: Is there an ideal water level to be maintained in the reservoir?

A: Start with the bare root submersed to the base of the rooted stalk, being sure to not submerse the stem or stalk tissue so as to avoid water logging. If using a wicking substrate, ensure the cube is approx. 1“ above water line; this may necessitate hand watering for a few days before the roots hit the water.

Q: What are the potentialities for plant steering using water level / amount of root zone exposed to the air?

A: With water as their growing media, growers can tailor nutrient solution parameters more specifically. Provoking plant responses such as essential oil production, fruiting and flowering are better manipulated when the substrate can be dialed in. For example, higher exposure of the root zone to atmospheric oxygen can help trigger a plant to increase oil production as a means to conserve water, and can also apply mild root stresses that are often interpreted by the plant as reproductive cues. While higher water levels can cause plants to focus more energy on vegetative production, particularly fan leaves, which in turn speeds transpiration and photosynthetic potential.

Q: Are there any specific pests or pitfalls DWC growers should watch out for?

A: Root diseases no doubt, Pythium, Fusarium, etc. These types of problems are most evident in water culture given the roots high profile, but are also typically found in most hydro methods currently practiced. In our experiences we’ve observed that once the variable causing the problem is removed (warm water, too high an EC, sludging inputs, etc.), it’s completely likely the plants will recover. In other words, root disease is not a death sentence, but a symptom of a problem needing to be addressed.

Q: I have heard from a few DWC growers that veg times can be significantly reduced, is this true?

A: Growers will need to make that call, but when dialed-in there is no faster way to grow plants—hydroponically or otherwise. A well-hydrated plant typically grows more quickly which will inevitably create shorter veg times and still achieve a premeditated harvestable plant size.

Q: Is DWC suitable for longer-term plants, such as donor plants? Commercially DWC is only used for lettuce and short-cycle plants, not for annuals.

A: Water culture is still a relatively new hydroponics method. Though first introduced in the 1930s by professor Gericke at UC Berkley, using water as a primary growth medium is still seen as somewhat impractical by commercial farmers. Due to the need to keep water conditions cool, it’s caused the bottom line to operate large-scale water culture facilities to be cost prohibitive.

Though with the recent improvements in cooling technology and increased efficiencies, I think we are likely to see a move toward water culture as a viable alternative to the current carbon substrate-based approaches presently being used for the growth of annual vegetables.

Especially as farmers discover the reduced volume of fertilizer inputs and the conservation of precious water that are key to water culture’s allure. This is an exciting time for water culture as what has been considered a black art is now emerging as a legitimate means of cultivating a variety of crops.

Vertical Growing in a Nutshell

“Noob” growers often scratch their heads when they first hear about the concept of vertical growing. “Don’t plants grow upwards normally?” they ask. So let’s get the difference between horizontal (regular) growing and vertical growing sorted out straight away.

Horizontal growing

Vertical growing

Horizontal growing is how most gardeners (indoor and outdoor) work. Plants are grown in pots or systems along a horizontal plane, and the grow light/s are positioned above the plants, mounted in a reflector so that the light gets beamed down to where it’s needed.

Vertical growing involves positioning the plants in a 360-degree formation around a grow lamp (sometimes in a cool tube but using no reflector). The general idea is that you maximize the use of the height in your garden, and make the most all that precious light energy without the use of reflectors. Plants in vertical growing systems tend to be a lot smaller, meaning shorter veg times but far greater plant numbers.

Growers’ Backgrounds

Everest: Okay guys, thanks for joining us. Now I know you’ve been blasting each other on the forums and you’re probably bursting at the seams to get going with this one, but first, can you each talk a little about your growing experience so the folks out there have an idea about where you’re both coming from?

Ian: Sure—I’ve been growing indoors for just over ten years. I started with potting soils, played around with most hydroponic systems (NFT, drip, ebb and flow, aeroponics) and a huge variety of growing media, and now I grow with coir using pots in a homemade drip system. I’ve stood by while some of my friends tried, and mostly failed, with vertical growing systems and even helped a few manage them for a while, which is why I would never recommend one to an interested grower.

Everest: Easy now Ian, we’ll get to all that. What about you Simon?

Simon: Well I’ve been growing on and off for around 15 years. I started with soil; I think 99% of people do. Then my local grow store switched me on to coco. I’ve tried clay pebbles too, sometimes mixed with rock wool croutons. I’ve run ebb and flow, NFT, drippers you name it. I’ve tried and failed with aeroponics but, to be honest, it was down to my ineptitude rather than anything else. But unlike Ian I don’t dismiss a technique out of hand just because it didn’t work for me. I’ve been running an Ecosystem since they came on the market. I’ve got my best results ever from vertical growing—it rocks!

Ian: Hang on, I’m not ‘dismissing’ vertical growing and, no disrespect, but personal bests are relative to the person. I’m just here to argue that vertical growing systems are not all they’re cracked up to be. I’m not even going to bring into the argument the phenomenal cost of vertical systems, which is enough to put a lot of people off. I want to focus on the practicality of using these systems, and why they suck.

Practical Considerations

Simon: There you go again. Why do you have to say “they suck” like that? I’m here to, hopefully, participate in an intelligent discussion about vertical growing. You mentioned practicality. Well, first off, vertical growing systems are a cinch to set up. Take the Ecosystem and Ecosystem 2 for example. They are ready to go gardens: lights, growing media, irrigation, reservoir—ready, steady, grow. All you need to do is take care of the growing environment.

Ian: You make it sound so easy! Ha ha. But ok, this I’ll give you. Some vertical growing systems are very quick and easy to set up. Others though, are a horrible arduous chore! I’ve had the joy of filling a Coliseum—300 plant sites with 3 x 1000 W lights—with a 265 gallon mix of perlite and vermiculite and, boy oh boy, it was a nightmare! It took the two of us the best part of four hours, and I’m not talking transplanting, just filling the system with growing media! Never again!

Vertical hydroponic systems are great for growing leafy herb crops in a small space as well as fruits and flowers. Note how this grower chose not to utilize all the planting sites.

Simon: You’re talking about growing 300 plants. And duh, guess what, that involves preparing 300 plant sites. Sorry if you’re work shy Ian but, of course, it’s going to take some labor to prepare! If I could find a system that filled itself with grow media, emptied itself, and replanted itself, I’d probably go for that, but …

Ian: Now you’re being both dumb and facetious Simon. But at least you’ve made a salient point against vertical growing on my behalf! Aren’t we really talking about making the most from your grow lights—in this instance, 3 x 1000 W. Don’t we need to ask why 3 x 1000 W grow lights should necessitate 300 plants in the first place!? It could just as easily light 18 large plants in five-gallon pots, spread over three, 5 x 5 ft ebb and flow trays. It’s going to take me … what … 10 minutes to fill 18 pots, not four hours to fill 300 plant sites?

Simon: And how long to veg up those “18 large plants” you mentioned?

Ian: Well, with six plants under a 1000 W … 10 days, maybe two weeks?

Basil gone crazy in a Coliseum! Regular cut and come again harvesting will keep this wall of basil in check!

Simon: (Cackles) two weeks! That’s ridiculous! Compare it with my two-day veg time for micro-plants in a vertical grow. My crop cycles are nearly half a month less than yours. You’re getting what … a maximum or five crops a year, whereas I’m always pushing six, using less energy too as I don’t have to have veg lights on for 18 hours a day for two weeks—ouch! I wouldn’t like to see your electricity bills!

Ian: But what about your plant numbers dude! They must be astronomical! In vertical systems you need anywhere between 80–300 identical cuttings for a two- or three-light system. In my four-light room I grow 24 plants, and to prepare for this I take 40 cuttings from one donor plant. Seems a little excessive to some but I only select the healthiest 24 with identical branch and node formation, the others I trash or give away. This selective approach helps me achieve a very uniform crop, level canopy and consistent yields.

Everest: That’s all cool and the gang, but what about Simon’s point on veg times and energy usage? Doesn’t that concern you at all, Ian?

Ian: Well it all sounds so wonderful in theory doesn’t it? Veg under metal halides for a few days and transplant into the system and bosh—straight into flower on a 12/12 light cycle. That’s what my buddy did and he found, due to the small veg time in the system, that some plants did not establish well enough and got left behind while others over grew and over shadowed them.

Simon: I’ve had that problem too. I overcame it by making sure that roots were simply exploding out of the rock wool cubes before transplanting into slabs. (Not just one or two.) I make sure those slabs have been pH adjusted and I water in my transplants individually with some CANNA Rhizotonic and a mild, balanced bloom formulation at around EC 0.8 and pH 5.5 – 5.8. I veg in the slabs horizontally for a couple of days, allowing the cuttings time to anchor in a little. Some plants will always outperform others—that’s natural. But I still end up with a beautiful canopy, either way. The trick with vertical growing is to select the right sort of phenotype that doesn’t stretch and get all gangly. You need to really know what you’re dealing with.

Ian: Yeah, yeah, but back to uniformity of cuttings for a moment; it’s easier said than done. And it’s so important to get right with vertical gardens, where plants are grown very close together and need to be kept small and squat, so identically sized cuttings are even more essential. This means for a 300-plant system I would have to take at least 400 cuttings (preferably 500), which means needing loads of huge donor plants to take them from. For my four-light room, I have a two-tiered shelved propagation tent, which is 4 x 2 x 4 ft, this houses two short stocky mother plants and my cuttings. To take a batch of 400 cuttings you’d need an additional two-light grow room! How is that saving space, let alone energy? It’s just shifting it all somewhere else! The whole thing’s a poorly marketed gimmick.

Simon: Yeah, you need lots of uniform cuttings to make vertical growing work, and not all plant species or varieties are suitable. Yeah, you need to know what you’re doing. I wouldn’t suggest this technique to a beginner. But the fact remains, I’m pulling six crops a year, you’re pulling four or five. I produce the 140 cuttings I need for my Ecosystem from two bushy mother plants under two x 400 W metal halides. Perhaps they aren’t always as uniform as I’d like though. More mother plants would help. I root them in several standard propagators under two banks of High Output T5 Fluorescents. And I veg them into rock wool slabs for two days under 250W metal halides.

The Ecosystem 2 boasts many improvements over its predecessor including a separate reservoir, increased number of plant sites, and more versatility with choice of growing media.

Ian: But two days isn’t enough veg time. The plants can’t lay down good foundations for their flowering cycle in such a short space of time. Also, wouldn’t you agree that with vertical growing it’s not about less work for the grower, it’s more that all the work shifts to propagation? Stressing over hundreds and hundreds of cuttings is not my idea of enjoyable indoor gardening. I’d rather be chilling and admiring my plants in my flat bed garden.

Simon: Well I guess we’re going to have to agree to differ on that one. Chill all you want with your five crops a year. I’ll happily “stress” over my six crops a year, thanks very much!

Ian: Yeah, I know yearly yields can be increased with short veg times, but six crops a year can be done with sea-of-green growing in horizontal gardens too, not just in fancy vertical systems. I’ve played around with higher plant numbers using ebb and flow trays, and can appreciate the quicker turn around, but as I’ve already said, the time and effort invested in preparing the garden and propagating the plants to get these larger yields is not worth the effort in my humble opinion.

Cool Tubes

Everest: Okay, let’s move on to another key component of vertical systems: cool tubes. Most vertical systems use glass air-cooled tubes to remove the heat from the lamp so the plants can bask closely to the light.

Ian: Yeah, but surely these tubes lower the amount and quality of light reaching the plants? I chatted to the guy at my grow store about this and he reckons that curved glass reduces light intensity by around 5% in comparison to flat glass which is around 3% compared to the open style reflector. Also, light tubes are not user friendly; I like to veg and finish my plants with metal halide lamps, using HPS in-between. Ever tried to swap out the lamps on a vertically mounted cool tube when there are loads of plants in the system? Trust me, it’s not easy.

Simon: Sure, glass stops UV (which promotes the development of essential oils) and diminishes light intensity a little, but this is all more than counteracted by the fact that you can get your lights closer to your plants. Also, many Ecosystem growers here in Montreal don’t use cool tubes at all; they simply drive lots of fresh air through the system. I’ve seen plants just inches away from 1000 W lamps! With enough air movement, they’re okay.

Ian: You’ve got to wonder about the potential for all those plants crowding out a cylindrical vertical growing system; there’s a fixed distance between the light and the canopy, which cannot be adjusted on most designs. This means as the plants grow from the system toward the light, the total canopy size decreases as the crop grows! Think about it. Most vertical systems are circular; as the crop grows it gets closer to the light so the circular crop canopy starts off the same size as the system and gets smaller as the canopy approaches the light. Not to mention the plants grow into an area of high light intensity, perhaps too high, as well as into an area of higher temperature. The only way to get around this is to have the option of moving the plants further away from the central light column, and most vertical systems simply don’t have this functionality.

The Shark Cage also uses rockwool slabs but can also be stacked.

Simon: You need to get multiple factors right for a good vertical grow: a plant variety that doesn’t stretch and go all leggy; the right number of those plants, and the right amount of veg time. Most growers who mess up in vertical simply over-veg their plants.

Ian: Yeah, but all the planning in the world doesn’t make up for a hot spell that causes your plants to stretch. There’s just a lot less margin for error in vertical grows. Whereas in my horizontal garden, I simple lift the lights when I need to, with no reduction in canopy size.

Simon: But what about efficiency! Growing plants 360 degrees around a lamp means every photon has a direct path to a leaf, rather than relying on reflectors (which can reportedly shift spectrums and collect heat) to bounce them.

Ian: This argument for vertical growing is the most common and convincing—you get to make the most out of the light emitted from the whole lamp, without the use of a reflector.

Vertical Grow Species Selection

You HAVE to use plants that grow short and stocky, and have extremely tight internodes. Experience with growing the variety in horizontal gardens is a must. You need to know the ins and outs of every aspect of the plant before attempting to grow it successfully in a vertical garden: Is it particularly susceptible to transplant shock? Does it produce fast, anchoring roots? How much stretch does it put on when triggered to flower? Does it respond well to frequent pruning into a single stem? Can it support its own weight without any plant supports? It is resistant to fungal diseases, particularly botrytis?

Simon: Finally, you’ve managed to say something positive about vertical growing.

Ian: Don’t get too excited. I’m not done yet. With almost all growing systems, the workload is more at the beginning and end of the cycle, but with vertical growing the workload can easily lead to a lack of motivation to get going again. The timing has to be spot on to get the crop cycles right and it’s no easy task. The buddy I helped with the Coliseum took at least a week to turn around a harvested crop into a newly planted one, which obviously ate into the salesman’s promise of six crops a year.

Vertical Grow Environmental Control

Maintaining short, stocky plants in a vertical growing system is a must. Poor control over temperatures in your indoor garden can easily lead to high day-time (lights on) temps and comparatively low night-time temps; the exact opposite of what you want for good short stocky growth. Tight environmental control can help prevent overcrowding. Having a small or zero temperature difference (dif) between day and night will keep plants short.

Simon: Nobody said getting bigger yields was easy Ian, unless you believe the less scrupulous nutrient manufacturers who just want to sell you three different bloom boosters and nineteen bottles of supplements.

Ian: That’s a whole ‘nother story! The only real advantage of vertical growing, as far as I see it, is a saving on floor space. Similar yields can be achieved with horizontal gardens with the same amount of light, and a lot fewer plants. It maybe true that once completely dialed in, the increased lighting efficiency can help increase yields, but certainly not by double as I have seen in some marketing literature for vertical grow systems. I would rather use an extra light and a few extra plants in a horizontal garden, than go vertical.

In the last issue we talked about just what aquaponics is (the marriage of aquaculture and hydroponics) and how it works. I described system types and then went into some detail about the creatures that live in a media-based aquaponics system: fish, plants, bacteria, and worms.

This article is the second installment in the two part series. We will now focus on what you need to know in order to build a media-based aquaponics system, including considerations about the fish tank, the grow bed, the plumbing, and the media.  So let’s dive right in.

Fish tank

The size of your fish tank will define the ultimate size and flexibility of your aquaponics system, so consider the tank size early in your design process. If you are building a small, desktop system using an aquarium, you will be restricted to aquarium fish that will live comfortably in the size aquarium you own. If you want to grow larger, edible fish, the most important rule-of-thumb when choosing a tank is to make sure it is made of sturdy, food-grade or food-safe materials. Next, make sure that the tank is at least 18” deep (457mm), and holds at least 50 gallons (189 Liters) of water. Tanks need to hold approximately 50 gallons (189 Liters) or more in order to grow “plate sized” fish (12” and 1 ½ lbs, 300mm and 680g).

Aquaponics fish tanks can be made from just about any structure that has satisfactory dimensions. They needn’t even hold water – just line them with EPDM pond liner. You can also use everything from recycled bathtubs, stock tanks, and IBC tanks, to recycled barrels.

Since you will find it difficult to move your fish tank once you fill it with water, you should carefully consider where you place it. Ideally the fish tank should be located indoors or outdoors in the shade. Fish don’t require sunlight to thrive and the extra heat and algae growth from sunlight can become a problem. Also, be sure the tank is on a solid surface that can handle the weight of the tank when filled with water. At 8.3 pounds per gallon, you will quickly reach a weight that might exceed the structural limits of the surface you are planning to use.

Wherever you choose to set up your tank, you will be well served to at least partially cover it to help prevent debris, children, and pets from falling in. Covering it will also lower the amount of light reaching the tank. This will help you keep control of the tank’s temperature and reduce algae.

Grow bed

Fish tank volume governs the maximize size of your grow bed. Here is why. The plants need the fish waste to thrive. The bigger the grow bed and thus the more plants, the more fish waste required. Simple – you need enough fish to support your plants. In general the recommended grow bed to fish tank ratio is approximately 1:1, i.e. the fish tank volume should be approximately equal to the volume of the grow bed. This ratio can also be thought of in gallons per cubic foot, striving for 6 gallons (22 liters) of fish tank to every cubic foot of grow bed. For example, a 50 gallon (189 liter) tank would be able to support 6 to 8 cubic feet of grow bed. You can extend this rule of thumb all the way to 2:1 (twice the fish tank volume to grow bed volume) but be sure to reduce the stocking density of your fish tank accordingly as this approach reduces your ability to filter the fish tank water with the grow bed plants.

Aquaponics grow beds should be about 12” deep (300 mm). 12” provides enough depth to support most plants and encourages the bacteria and composting red worms in the grow bed to fully establish themselves. A 12” deep bed never needs to be cleaned out because the robust eco-system enabled by a 12” deep grow bed takes care of this for you. Below is an excellent explanation by Australian Murray Hallam of grow bed dynamics – reprinted with permission from his new Aquaponics Secrets video:

Surface or dry zone (Zone 1) - The first 2” (50mm) is the light penetration and dry zone. Evaporation from the bed is minimized by the existence of a dry zone. This dry zone also protects the plant base against collar rot. Additionally, by ensuring that this zone is kept dry, algae is prevented from forming on the surface of the grow bed and moisture related plant diseases such as powdery mildew are minimized.

Root zone (Zone 2) - Most root growth and plant activity will occur in the next zone of approximately 6” – 8” (150 – 200mm). In this zone, during the drain part of the flood and drain cycle, the water drains away completely, allowing for excellent and very efficient delivery of oxygen rich air to the roots, beneficial bacteria, soil microbes, and the resident earth/composting worms.

During the flood part of the cycle, the incoming water distributes moisture, nutrients and incoming solid fish waste particles throughout the growing zone. The worm population does most of its very important work in this zone, breaking down and reducing solid matter and thereby releasing nutrients and minerals to the system. “Worm Tea”, as it is commonly known, will be evenly mixed and distributed during each flood and drain cycle. “Worm Tea” and the fish are entirely compatible.

Solid collection and Mineralization Zone (Zone 3) - This is the bottom 2” (50 mm) of the grow bed. In this zone fish waste solids and worm castings are finally collected.  The solid material has been reduced by up to 60% by volume, by the action of the resident composting worms, and microbial action. During each flood and drain cycle, what is left of the solids percolates down into this zone further and final mineralization occurs in this area via bacterial and worm activity. Due to the excellent action of the flood and drain cycle, this bottom area is kept “fresh” and vital by the excellent delivery of oxygen rich water during the flood cycle.

Warning: Do not use metal containers, not even galvanized metal, for either the grow bed or the fish tank. Metals can quickly corrode, throwing your system off-balance by lowering your tank’s pH. Metal containers may also leach undesirable chemicals into your system. Copper and zinc are particularly dangerous to fish. As with the fish tank, make sure the grow bed you choose is made of sturdy, food-grade or food-safe materials.

Media

The growing media should be inert, meaning that it should not be biologically active or decompose. This enables the best bio-filter for your fish waste and the cleanest system overall. Most aquaponic gardeners use either gravel or expanded clay pellets (e.g. Hydroton).

If you use gravel, it should be ¾” (20mm) to 1” (25mm) in diameter in order to optimize the air exchange within the media for the roots of your plants. Caution: be certain you know where the gravel is from. Many types of gravel, especially granite, can leach lime and other elements, which will adversely affect your pH levels and potentially kill your fish, plants, and bacteria. Marble also tends to increase pH to levels that can quickly be fatal to bacteria, and eventually the fish and plants.

Expanded clay pebbles are more expensive than gravel, but are 50% lighter and more porous so they have optimal gas and water exchanging properties. Best of all, because of their round shape, it’s easy on your hands, roots and stems of your plants – making planting and maintaining your system a pleasure. Plus, you will have no worries as to where it came from! We think it is worth the investment because you will have it for the life of your aquaponic system.

The top 1 – 2” of your grow bed should be left dry to help prevent fungus, gnats, algae problems, and moisture related diseases (see the Dry Zone above).

Plumbing

Flooding the grow bed delivers nutrients to the plants and the bacteria; draining the bed oxygenates the water, the plants roots, and the bacteria. Systems using this method are called flood-and-drain or ebb-and-flow systems, and are what most media-based aquaponic systems employ.

There are three standard flood-and-drain style plumbing systems used in media-based aquaponics: timer based, bell siphons, and flush valve systems.

Timer based systems are the most common and the easiest to install. They are comprised of four components: the water-in pipe, the over-flow drain, a timer, and the pump. To set up a timer-based system you simply attach a pump to a timer and set it to power the pump for 15 minutes every 30 – 45 minutes. While this is much more frequent pump activation than in a traditional hydroponics system it is necessary to provide sufficient oxygen to the fish tank, sufficient filtration for the fish, and sufficient oxygen in the grow bed for all the biological activity (as the water drains from the bed it pulls oxygen behind it through the bed).   Since pythium (root rot) is almost non-existent in aquaponics there is no increased danger of disease because of this increased irrigation frequency. Next place the pump in the fish tank and attach the pump to the water-in pipe that goes into the base of the grow bed. When the pump is activated, water will move from the fish tank into the grow bed until it reaches the level of the overflow drain. The overflow drain should be set to drain at 11” so that the top one inch of the grow bed will be left dry. After 15 minutes of flooding the grow bed, the timer will turn the pump off, allowing water to drain back through the water-in pipe and out through the pump. Though this system is common and easy to install, the downside is that turning the pump on and off can shorten the life of the pump.

In the bell siphon (AKA auto siphon) system the water pump constantly pumps water from the fish tank into the grow bed. As the water rises, it fills the interior of the bell siphon positioned within the grow bed. When the water reaches the right height, it spills over a pipe within the siphon and creates a low pressure area within the siphon that triggers the siphoning action. The siphon rapidly draws the water from the grow bed into the fish tank until the grow bed is nearly drained, at which point air enters the siphon, the low pressure within the siphon is lost, and the siphoning action stops. Since the pump is always on, the grow bed begins to fill once again and the cycle repeats. This may seem confusing at first, but the bell siphon system can be a great option to explore, as leaving the pump on at all times will increase the longevity of the pump. Plus the extra heat that the pump may generate is actually a benefit to aquaponic systems growing fish that prefer warmer water.  Again, because pythium is so rare in aquaponics the extra heat does not pose an increased risk of disease. There are many excellent videos about the construction of bell siphons available on the internet.

Flush valve systems work very much like a flush toilet. This system requires that a flood tank be added to your fish tank and grow bed setup. The flood tank, being similar to the tank of a toilet, is placed above the grow bed. The grow bed, being similar to a toilet bowl, is placed below the flood tank with the fish tank being the drainage point. Water is constantly pumped from the fish tank into the flood tank. A small siphon collects water that fills a container, which acts as a weight. Once the water is heavy enough it triggers a standard toilet flush valve. This then allows water from the flood tank to drain into the grow beds and then into the fish tanks. The water-filled weight has a hole in it that makes it drain slower than it is being filled, so once the flood tank has emptied the small weight begins to drain. Once the small weight has drained it again is light enough to close the standard toilet valve, re-initiating the cycle.

The pump is the heart of an aquaponics system. When you select a pump, consider a simple rule of thumb – choose one that can, at a minimum, cycle the entire volume of your tank in an hour. If, for example, you have a 100 gallon (375 Liter) tank, than you will want a pump that can pump at least 100 gallons to the height of the grow bed every hour.

It is important to have backup aeration for your aquaponic systems. If your pump fails, your plants will be fine for a day or two but a few hours without moving water could lead to dead fish due to oxygen deprivation.

Starting up your system

So now you just put in the fish and the plants, plug in the pump and start growing, right? Not so fast! First you need to establish nitrifying bacteria in your aquaponics system, a process called “cycling”. Without these bacteria, the ammonia the fish produce will not be converted into nitrates, causing the fish to die from ammonia poisoning and the plants to starve from lack of fertilizer.

The key to cycling is patience. To initiate cycling, ammonia must be introduced to attract the naturally occurring nitrosomonas bacteria. After another two weeks, or so, the existence of nitrites will attract nitrobacter bacteria. This second type of bacteria is what will change the nitrites into nitrates. Nitrates are nearly harmless to the fish and are consumed by plants as food, therein filtering the water. After approximately 30 days of cycling, you will reach your goal – low ammonia levels. Now you can fully stock your tank and plant your grow bed. For even faster ways to cycle your system, read on..

The Nitrogen Cycle

There are many ways to introduce ammonia to initiate the cycling process in a fish tank. These are generally broken down into two categories: with fish and fishless cycling. Most people use live fish to introduce the first ammonia to the tank and start the nitrifying process. Since ammonia is poisonous, and there will be no bacteria to convert the ammonia for a few weeks, assume these introductory fish are “sacrificial” and may not survive.

If you choose this route, avoid pet store “feeder fish” since, generally speaking, they tend to already be diseased or near death due to poor conditions. Black skirt tetras, goldfish, zebra danios and barbs are good choices to start cycling your tank. Only feed these first fish once a day during the cycling process.

If you prefer cycling without fish, you can initiate the cycling process by introducing small amounts of pure ammonia (clear ammonia, 100% ammonia or pure ammonia hydroxide), vermicompost, or “humonia” (also known as “pee-ponics” where one urinates into the system to introduce the ammonia).

You can speed up the process by actually introducing the nitrifying bacteria yourself with river or pond water, filters or gravel from an already established tank, or with commercial nitrifying products.

Whether using fish or fishless cycling, it is important to use a test kit to monitor the system daily so that you always know what part of the ammonia cycle the system is in. Be sure to keep the pH between 6 and 8 (at 8 or above the cycling process stops and the ammonia becomes highly toxic) and the water temperature above 50°F/10°C (80°F/27°C is optimal).

Once your ammonia and nitrite levels drop and nitrates begin to appear, it is safe to add plants and fish to your system. If you stick with the recommended fish stocking density (no more than 1 pound per 5 gallons of water), keep your beds fully planted, and follow all the other recommendations in this article, you will find that your grow bed grows better and better with time. Happy gardening!

WORDS: Sylvia Bernstein

New York restaurateurs, John Mooney and Mick O’Sullivan, could easily use one of many farmers’ markets in the Manhattan area to keep their pantry stocked with fresh produce. Instead, however, the industrious pair decided to keep things even closer to home by setting up a hydroponic garden on the roof of their soon-to-open restaurant, Bell Book and Candle. John and Mick’s vision is to provide the majority of what appears on their customers’ plates directly from the rooftop, with all the freshly-picked produce lowered by a pulley system straight into their kitchen.

Chef John Mooney collects his bounty

The restaurant’s garden, on the rooftop of 141 West 10^th Street between Waverly Place and Greenwich Avenue, Manhattan, is now home to melons, mint, garbanzo, tomatoes, lettuce, and much more.  Their produce is grown in sixty vertical tower hydroponic systems, designed and engineered by Future Growing LLC., of Orlando, Florida. These incredibly productive, self-contained growing units allow Mooney and O’Sullivan to grow all the produce they need for their 94-seat restaurant in a relatively tiny space. The plants and white roof lining also help with keeping the building cooler in the summer.

“We went through several years of marketing and trials,” explained Tim Blank, founder of Future Growing LLC., “to develop the Tower Garden system. We never went mainstream with it until now. In the last five years we’ve made over a hundred tweaks to the system to get to the unit we have today. We found that generally people were confused by hydroponics, especially by nutrients. There are so many different types for different stages of growth and bloom. We thought there’s got to be a way to make hydroponics more accessible and relatively easy to do at home. Now we’ve simplified things enough so that two chefs, without any hydroponic experience, can manage their own roof-top farm of well over 1,000 plants.”

Rooftop solar panels help to power the irrigation system.

Amazingly it took just four days to transform the rooftop from plain black asphalt to a fully functioning rooftop hydroponic oasis! Plant starts were initially brought in from a nursery in Philadelphia but now the chefs take care of that too.
“It’s vital that the system was simple enough for anybody to use,” Tim explained. “John and Mick, like all business owners, need to stick to a strict budget. They can’t afford to hire in a full-time gardener to take care of their plants for them.” Now, just six weeks after installation, the only challenge is keeping up with the speed of growth!
“We’ve shaved 25% off the normal time needed to grow lettuce,” chef John Mooney told us. “Now we can go from seed to harvest in just four weeks! It’s incredible!”

The Tower Garden works by stacking growing units on top of a 25-gallon reservoir. Nutrient solution is pumped to the individual plant sites where the plants thrive in an oxygen-rich, soilless environment. The irrigation system is set on a timer watering the towers for three minutes out of every twelve. The Tower Garden is made from white, food-grade plastic, enhanced with UV protection so that it holds up in the unforgiving outdoor environment.

Now that’s what I call an Urban Garden! We look forward to the day when all rooftops will look like this!

Despite the sometime extreme New York weather, John and Mick are confident that they can grow on their rooftop for ten months out of twelve. Even when temperatures occasionally drop to below freezing a nutrient heater can be installed in each reservoir and irrigations are set to constant, rather than intermittent, so the roots are bathed in 65°F water. This creates a microclimate around the plants so that they can survive the odd cold snap with ease.

Mooney believes that his rooftop garden not only drastically slashes his shopping bill, but also serves as a model for others who will need to start growing food closer to home.

Plant sex in the city! Several varieties of bees have already found the rooftop garden and regularly swarm around the heirloom vegetables, doing what they do best!

“I believe in ingredients. I’ve always believed in responsible sourcing. And now I can produce what I need right here in abundance.” The chef-gardeners don’t use any pesticides. Instead, a vast population of beneficial insects protects their crops from bugs. Unbelievably, these beneficial insects found the garden—all on their own—high up in the middle of Manhattan. The rooftop is also frequented by a vast array of different bee species, all helping to keep their heirloom vegetables, including okra and red tomatillo, pollinated and productive.

“I was stunned.  There are several varieties of bees swarming the plants. From bees you could hardly see to gigantic bumblebees. Here we are in the center of New York! I have to hand pollinate my squash in Orlando! I almost dropped to my knees in awe! Ladybugs everywhere. Lacewing eggs everywhere! Predator wasps everywhere! In six weeks we’ve created an entire ecosystem!”

Inspired? We thought you would be! Bell Book and Candle is due to open to its first customers this fall.

What’s Growing?

Bell Book and Candle’s garden boasts over 70 varieties of herbs, vegetables and fruits for its lucky diners including:

Bell Book and Candle: www.bbandcnyc.com

Tel: 212 414-2355

And if you are interested in finding out more about the Tower Garden hydroponic system visit www.mytowergarden.com or come along to GROW 2010 in Los Angeles for Grower Day on October 2^nd.

DESIGNING A HYBRID AERO-FOG-SWC SYSTEM

This system irrigates each plant in three different ways, yet it’s blissfully simple. It’s essentially a modular re-circulating system which incorporates: shallow water culture (SWC) aeroponics misters and aeroponic foggers.

Each plant gets the VIP treatment, basking in a 20 gallon Rubbermaid container! Wow! There are 70 plant containers in total. They are all joined together via ¾” tubing. Nutrient solution is pumped from an underground 55 gallon reservoir with a 1546 gallon per hour pump to the middle of each container. Within each container there’s a large ¾” flexible PVC irrigation ring with 3 x 180° misting nozzles ready to rumble. When the misters are on, the container gets filled with small droplets of nutrient solution, the droplets that don’t get absorbed by the roots fall to fill the bottom of the containers. As the container fills past 2.5 gallons, the solution reaches an overflow tube, from here it returns through ¾” PVC pipe back to the main reservoir.

After running a few tests Devin adjusted the return pipe to the reservoir to make it a more direct return. The foggers are set to spray for almost 7 minutes on and off for 4 minutes. This timing is deliberately adjusted so that sometimes there is only fog, sometimes fog and sprinklers, and sometimes sprinklers half the time and fog half the time. The timers are set so that different watering techniques are activated at different times in different combinations. The logic is the plant won’t get too used to anything and it also allows the root zone to dry a little, encouraging the root hairs to go in search for food. This makes the roots very tenacious, white, and strong.

As soon as the solution returns back to the 55 gallon from the overflow the system kicks back on. The return takes almost 4 minutes. When spraying the roots, the solution comes from the 55 gal reservoir, and it takes just 7 minutes to empty the 55 gal. This is the maximum watering duration that Devin feels he can achieve without getting a bigger reservoir.

In the bottom of each container is a 4” air stone, these are connected to 4 x 750psi air compressors to infuse the 2.5 gallons of nutrient solution with oxygen rich bubbles. Sounds just like an interesting re-circulating system right? Well here is the secret to this high yielding system…

Each container has an aeroponic fogger floating just under the surface of the nutrient solution. Each fogger has three disks. These foggers are on a 5 minute on, 5 minute off cycle to create an extremely fine mist or ‘fog’ with a particle size of 3-5 microns! Such a fine fog of nutrient solution creates supercharged roots with an abundance of fine root hairs. These root hairs can take up water and nutrients at a rapid rate creating explosive plant growth. This technique of utilizing ultra sonic foggers to deliver a nutrient fog to the roots has been recently dubbed ‘Fogponics’, although officially it falls under the banner of aeroponic cultivation.

AEROPONIC FOGGERS

Aeroponic foggers come in various shapes and sizes but all utilize the same technology. They work by sending ultrasonic frequencies to ceramic disks which sit just below the surface of the water. These ultrasonic frequencies vibrate the disk which oscillates the water above creating an ultra fine fog. This fog has such a small particle size that it feels dry to the touch yet it can easily penetrate roots without totally saturating them.

CHALLENGES

1) Foggers

The main drawback of using most foggers with nutrient solutions is they can become clogged very quickly with nutrient precipitate. Even using foggers in hard water alone can cause a quick build up of lime scale, let alone adding mineral salts to the mix, so how does this extreme aeroponic system get around this?

Through trial and error and with some help from Ryan Clout at Sunflower Supply and the online garden forums, these crazy cats found a solution. Devin located a company online selling Teflon coated disks that are longer lasting and keep residues from building up on the disk surface. This drastically prolongs the life of the foggers reducing the need for constant cleaning and frequent replacements.

As mentioned previously, the foggers need to be just below the surface of the water in order to emit the ultra-fine fog. To enable the water level in the container to rise and fall while still allowing the fogger work it became clear that the fogger would have to float. So armed with a tiny budget and a trip to the dollar store, the floats for the foggers were created from play snorkels and net cups for only a dollar for each fogger!

2) Solution Temperature

While in operation, the foggers generate a significant amount of heat that gets soaked up into the nutrient solution. Even with the solution circulating from a large reservoir around all the containers, the temperature of the solution in the bottom of the containers was quickly rising to beyond 75°F. Ideally the nutrient solution should be around 65°F for optimal levels of dissolved oxygen and nutrient uptake. This was a tough nut to crack. The way forward was to cool the nutrient solution and, being and inventive bunch of growers, they decided to make their very own homemade water chiller.

Using an old freezer (2ftx2ftx4ft) as the cooling chamber the crew drilled two ¾” holes through the casing, one near the top and one near the bottom. The cooling mechanism was created by constructing a coil made from 25ft of aluminum tubing. This fitted perfectly into a five gallon bucket which had a drilled hole at the top and bottom. This allowed the ends of the coil to come through. Then, they fed a ½” hose into each of the holes in the freezer, used silicone to seal the holes, and connected them to the coil lines. After making sure the hose and coil were watertight, they used non-toxic propylene glycol antifreeze to fill the five gallon bucket and popped a lid on it.

This homemade chiller is located next to the underground 55 gallon reservoir with the upper ½” hose connected to a pump in the bottom of the reservoir and the lower hose draining the chilled solution back into to the reservoir. This constant flow of nutrient solution being pushed through the chiller created a constant nutrient solution temperature in the reservoir of 60°F, with the containers stabilizing at 70°F, keeping the heat emitted by the foggers under control.

3) Environment

Being in the heart of Southern Oregon, air temperature during summer is also an issue for this aeroponic set-up. The roots are particularly susceptible to extremes in temperature as there is no growing media to act as insulation. On a nice sunny day, an outside temperature of 75°F can easily create up to 100°F in the greenhouse and that’s with the 24 inch ventilation fan and both 24 inch passive shutter inlets open! To keep temperature down on hot days a 25,000 BTU air conditioner was incorporated. It also doubles up as a heater for those cold nights in winter.

SYSTEM ENHANCEMENT

The secret to the system is the hybridizing of SWC, aero-sprayers, and the ultra fine fog creating by the foggers. Studies in the late 90s by NASA have shown that solely using ultra sonic foggers to feed plant roots creates a disproportionate amount of root hair with significantly less lateral root growth, making ‘fogponics’ less suitable for prolonged plant growth – i.e. bringing plants to full maturity. By combining the two aeroponic techniques of fogging and misting upper root zone and utilizing SWC to supply water, dissolved oxygen and nutrients to the lower branching roots, they have achieved the best of both worlds.

One key aspect of this hybrid system that Devin is keen on maintaining is a high beneficial microbe count, particularly predatory nematodes, in the growing media and nutrient solution. The beneficial nematodes are an excellent predator of fungus and bacteria, which Devin is sure will help keep the system clean.

To provide a good home for the microbes to hang out and breed, they have come up with a media mix for the net pots of 5 parts Hydroton to 1 part ‘loose fill’ Sure To Grow. Devin and the crew feel that this mix provides them with the ideal surface area for the microbes to stay happy.

To inoculate the system with tons of beneficial microbes they brew their very own worm compost tea!

DEVIN’S WORM COMPOST TEA

Step 1: To 16 gallons of reverse osmosis water, add 1 fluid oz (28.5ml) of fulvic acid and 1 oz of brewers’ yeast (used for home brewing beer and wine).

Step 2: Add 2.1 fluid oz (60ml) of Humboldt Honey Hydro ES to provide food and energy for the microbes.

Step 3: Add 4 teaspoons (20ml) of Cutting Edge Solutions’ calcium carbonate, the microbes to love it!

Step 4: Take 15” x 23”brew craft fine screen mesh bag and add 2.5 pounds of worm castings.

Step 5: Add and air stone (attached to an air pump) to the mix.

Step 6: Steep the worm casting bag in to solution for 72 hours.

Step 7: Remove the bag, give it a few squeezes and let the solution brew for another 12 hours.

Step 8: Prepare the nutrient solution, Devin uses Cutting Edge 3 part formula.

Step 9: Add the 16 gallons of fresh worm tea to 300 gallons of nutrient solution.

Using this technique the crew manage to brew a full 16 gallons for $15! With this fresh brew of beneficial microbes Devin says you can’t add too much. They even spray the mix on the plants in vegetative growth stage which they have found works best neat or at a minimum dose of 1 part tea to 5 parts water.

Using a plant viable form of calcium carbonate really works wonders. Microbes like to have some kind of nutritional buffer, whether it’s a little bit of potassium or even phosphorus, they just need some kind of mineral to feed off. Devin noticed that his nematode population is 10-15% higher when he used calcium carbonate. He used Cutting Edge Solutions’ calcium carbonate – once you open it you really must use within eight weeks, otherwise it can get susceptible to mold.

Using this concentrated homemade worm-tea the growers find they only need to use ½ to ¾ strength nutrient solution! The main reason is that the worm-tea contains a huge population of predatory nematodes and protozoa (single celled organisms that are found across several kingdoms). They are non algal, and non fungal (such as amoebaes, ciliates, and flagellates) and are the number one predators to bacteria and fungi alike. These little worm-like parasites are nasty little buggers. They are heterotrophic which means they cannot produce their own food. Instead they hunt bacteria and fungi while remaining harmless to you and your plants. They locate and shred apart the fungal mycelia and bodies of bacterial organisms which then provide plant available nutrients and minerals to the root system. It’s a beautiful circle!

Freshly brewed, actively-aerated compost tea and compost tea brewing machines with ready-to-use brewing kits are also available from several companies.

We recommend you check out:

• Vermi-T from Vermicrop Organics
• Progress Earth
• Nature Technologies International
• Bountea

To complete the beneficial microbe mix, they add other beneficial liquid additives. These include Canna’s Cannazyme and Botanicare’s Aquashield. Also, check out Sub Culture B from General Hydroponics.

Every two weeks they change out the nutrient solution for a fresh batch. To empty the system all they need to do is open up three taps – this allows the solution to run out through pipe work onto an outdoor vegetable plot, putting even the ‘waste’ nutrient to good use. To fill the whole system they prepare a 300 gallon reservoir which pumps the fresh solution to each container.

Devin has extensive hydroponic experience with flood and drain tables, drain to waste systems, Deep Water Culture, aeroponics, soilless and soil yet finds this hybrid shallow water culture/aeroponic/fogponic system the most sanitary, easier to clean with the least amount of nutritional and pest problems.

To provide support for the plants they use tomato cages fitted into the exterior of the net pots. This offers great support and allows the branches to be trained out, which in turn enables the plant access to more light, better support, more growth and more fruit!!!!

The assemblage of all these high yielding methods with a few tweaks has provided Devin and his crew an affordable homemade system that that they can literally (and physically) grow trees in!

WHAT DO YOU THINK OF THIS

SYSTEM? ARE THESE GUYS DESTINED FOR GREATNESS OR WHAT?

Special thanks to Ryan at Sunflower Supplies (www.sunflowersupplies.com) for his help with the ultrasonic foggers!

Day 122

Although very short lived and sparse, the flowers of this black radish are very pretty.
The acrylic crocheted netting (left) has held up much better than the cotton trial. In fact it appears to be in good enough shape to wash, and be used again.

The radish appears healthy (right), and I have every reason to believe that the system could continue to support a plant almost indefinitely.

While I wouldn’t exactly call it ornamental, it is interesting looking, and taller than I expected. Someday people are going to quit teasing me about my crochet hydroponics; but not today.

Today, Gentle Reader I give you version three: I started with two plastic colanders from a dollar store, lashed them together, made a hole in the top, and filled with perlite. The encasing shell and wick are crocheted as one seamless piece.

Then I suspended the “ufo looking crochet thing” over the pond, with the wick dangling into the water.My current plan is to top water the perlite to keep it moist, then as the roots grow down to the wick, allow that to water the plant, until finally the roots reach the water, and it begins to function as a deep water culture. At which time, the perlite globe will not longer be supplying moisture, but air. Peace, love, and puka shells,

Grubbycup ]]> http://urbangardenmagazine.com/2010/05/crochet-hydroponics-part-5/feed/ 2 http://urbangardenmagazine.com/2010/05/pond-hydroponics/ http://urbangardenmagazine.com/2010/05/pond-hydroponics/#comments Fri, 21 May 2010 20:10:18 +0000 Grubbycup http://urbangardenmagazine.com/?p=4628 Spring is in the air, it’s a beautiful day, let’s take some of our experiments outdoors. Just outside of La Mancha is a little pond… I know that there are plenty of nutrients in the water. I can tell this by the following observations:

• There are plenty of fish in the pond, and plant nutrients are a known result of fish.
• The spring algae bloom is prolific (more on that in a minute).
• The system is already supporting existing plants very well.

Fight it.

or

Don’t fight it.

Gentle Reader, I suggest you just learn to accept that the pond is going to look a bit green for a while once a year. After checking the piggy bank, and getting threatened with being turned over to the ASPCA if I don’t start feeding it a little something once in a while, I made the executive decision that this was going to be a budget minded enterprise. So perhaps a future version will include my aspirations to extend the deck, but for now, a couple of 4″x 4″s and a re-tasked wooden frame will form the base. Wicked pots sit on the platform. They will be top watered until the roots are established, then they should be able to pull pond water up the wick, and finally, send roots down into the pond itself. This is where I got even with the piggy bank. The piggy bank now exists only as an abstract concept of anti-existence. I bought two inexpensive “mini-greenhouses” for $30 US each. There are several things I like about these racks:

• They are light enough to sit on the wooden platform.
• Easy to put up.
• Great to scavenge parts from.
• The shelves make for a nice training screen.
• They were cheaper than what it would cost if I built it. I tend to get carried away.

This, Gentle Reader, is my process. I make a model, and learn from it. Then another, and another, sometimes I start making them a little bigger…

So when I take the plunge on expensive things like the solar panels and water pump (I want to use to pump the water up to a reservoir, so the only “house electricity” it uses is a valve on a timer), I can feel confident that the rest of the design will work.

Peace, love, and puka shells,
Grubbycup ]]> http://urbangardenmagazine.com/2010/05/pond-hydroponics/feed/ 4