Picture a highly experienced indoor gardener who has selected some awesome, tried-and-tested plant genetics and installed ample lighting with  a control unit regulating air-flow, a CO2-enriched atmosphere and perfect humidity. Last but not least, let’s imagine this gardener is using the best nutrients known to man (whatever brand that might be!) in an active hydroponics system.

All sounds rather slick, right? After all, the key to huge harvests is providing a whole spectrum of optimum conditions for your plants – like a series of links in a chain. However, there’s one thing missing from this garden – an essential building block of the sort of harvests your plants want to give you. MICROBES.

Beneficial Microbes

Microbes may be small, but they’re taking off in a big way as indoor gardeners discover new ways to harness the benefits they bring. And leading the pack is John Perrino of Vermicrop Organics, California.  He’s taken some time out from his crazy microbial world to explain what microbes are, what they do, and how we urban gardeners can use them to take our gardens to the next level.

Perhaps I shouldn’t attempt to summarize everything in the first sentence, but here goes: Beneficial microbes increase the efficiency of your nutrients. Put another way, microbes allow your plants to feed more. Even the highest quality nutrients can be made more efficient through microbiology, thus increasing growth, vigor, sugars and yields. Ok, so now you know what beneficial microbes are basically about – but let’s look a bit deeper!

The basic application of beneficial microbiology in soil and hydroponic gardening is simple, really. It kind of falls under the same concept as the food chain. When a plant’s root system has a well-rounded colony of micro-organisms, it has billions of microbes doing a wide range of jobs. Some microbes consume nutrients; some microbes consume the microbes that have consumed the nutrients, thus breaking the nutrients down into a smaller form. This allows the nutrient to be absorbed by the plant more efficiently. Other microbes defend against unbeneficial microbes and keep the plant’s natural defense system at its peak performance level. Each microbe exudes different types of enzymes, proteins, acids and other essential elements. These are the elements needed to break down trace minerals, micro nutrients, and macro nutrients making them immediately available as a food source to the plant. All this really means is an explosive increase in root mass, which equals increased nutrient uptake, which equals bigger yields!!!

So if these beneficial microbes are the building block to a robust and vigorous garden, how do we get them there in the first place? Remember, these little guys are living entities. So the best way to increase the levels of microbes in your gardening system is a fresh brewed, microbial rich solution. We are talking about Actively Aerated Microbial Extracts (AAME). Now, don’t switch off on me just because I’m using acronyms already. I’m telling you that AAMEs are going to change your life!  So listen up!

So What’s Brewing?

Actively Aerated Microbial Tea

Like I said, these little guys are LIVING so they’re going to need feeding. The idea behind AAME is to take an organic material that is high in beneficial aerobic microbes and add essential food sources to raise certain levels of each type of beneficial micro-organism. To get things to multiply, dissolved air and a food source in an aqueous environment is needed. But you have to create the right conditions for these little fellas to multiply at the rates we want – using water straight from the tap is a no-no (because of chlorine levels); reverse osmosis or de-chlorinated water at the perfect temperature and the right type of food sources will allow microbes to multiply at extremely rapid rates.

Beneficial Bacteria

There are three basic groups of beneficial micro-organisms (take note there are tens of thousands of individual types of each microbe in each group). The first to be addressed is beneficial bacteria, the smallest of the three groups. They attach to your root system and feed on unavailable nutrients in and around the root web. Once a bacterium has consumed a nutrient (food), the nutrient is then immobilized (locked inside of the bacteria’s cell wall).  Here the nutrient is broken down with a mixture of different proteins and enzymes. The only way that the nutrients can be unlocked (mineralized) and up-taken by the plant is if the bacteria dies and/or is consumed by a competing micro-organism. Once this process occurs, the nutrients are released in their mineralized form and are immediately absorbed by the plant.

Fungi

Fungi, the second group of beneficial micro-organisms, are much like bacteria in the sense that they too find and immobilize unavailable nutrients. Unlike bacteria, fungi find their nutrients in a completely different way. Fungi live in and around your root web, and grow miniscule root-like strands called “hyphae”; these strands can stretch for many feet. The hyphae stretch throughout the network of the plant’s root system, usually ending on an attachment site on the root. The nutrients are then distributed in a number of different ways. Immobilized nutrients are locked up within the cell walls of the hyphae until the fungal microbe dies and/or is consumed by a competing micro-organism. The nutrients then get mineralized and passed off to the plant as an “easy to absorb” food source. Other fungi trade exudates (carbohydrates, sugars and proteins made by plants and excreted by roots) for water and nutrients; these fungal organisms are known as mycorrhizae. Mycorrhizae work in a symbiotic relationship with the plant’s roots: the fungi brings nutrients and water back to the plant’s roots in exchange for exudates collected from the roots. It’s a win-win situation. The plant then becomes somewhat dependent on the fungi and the fungi cannot live without the exudates from the plant. Through this relationship, many different nutrients are mineralized and absorbed immediately by the plant.

Protozoa

The third type of beneficial micro-organism is the protozoa. Protozoa microbes can be up to 100 times the size of bacteria and fungi. The protozoa feed on mostly bacteria and fungi (protozoas can eat up to 10,000 bacteria a day). When the protozoa consume bacteria or fungi, they mineralize any of the nutrients that were immobilized in the bacteria or fungi. This unlocks any nutrients that have been locked up in the bacteria and fungi. They are then absorbed rapidly as a food source to the plant. Protozoa are at the top of the food chain in the beneficial microbe world. This means there always needs to be a food source, otherwise protozoa will die. Luckily, as the protozoa consume the microbes they consume small bits of organic matter that are processed and exuded as food sources for bacteria and fungi. This helps keep fungal and bacterial populations sustained when conditions are right. If fungal and bacterial populations diminish, protozoa will start to eat their own and eventually die. This is why it is important to replenish microbe populations with a balanced array of beneficial micro-organisms, keeping the food chain in balance and allowing optimal performance.

The only way to get an extremely high multiplication of micro-organisms is through a fresh extracted AAME. Unfortunately, Actively Aerated Microbial Extracts are not available as an ‘off-the-shelf’ product.  To solve this issue, an on-site extraction process with a culture of biology is necessary. This process can multiply the culture of aerobic micro-organisms over 9 billion times in a 24 hour period. When an AAME is used as a foliar spray and as a root inoculant, it will raise the number of micro-organisms that work together in a symbiotic relationship with the plant to increase vigor and yield. With a high diversity of beneficial micro-organisms, plants receive a wide array of the micro-organisms that exude humic, fulvic, amino acids and proteins. These micro-organisms and their exudates aid in immobilization and mineralization of trace elements, micro and macro nutrients.  Microbes have been around for millions of years and now we have the technology to put them to use in our gardens.

Microbe Tea – Q&A

You say actively aerated microbial extracts aren’t available ‘off-the-shelf’ – so once I’ve brewed the tea do I need to use it straight away?
No – think of it like milk. It will last for 12-24 hours if stored at room temperature, or 7-10 days in the refrigerator. Use the smell test. It should have an earthy and fresh aroma if it’s good. Smells damn awful when it’s gone bad!

How much microbial extract brew is good for my plants?
For Soil: Dilute with water at a rate of 75 ml to gallon (1:50). Apply this solution directly to your soil over the root zone.
For Hydro: Use the same dilution ratio but reintroduce more microbial tea solution to your nutrient solution every 7-10 days.

Can I use boiled tap water to make the microbial tea?
No, boiling won’t cut it. You must use non-chlorinated or Reverse Osmosis filtered water. Reverse osmosis machines are more affordable than you think. Check out the Small Boy made by Hydro-Logic.

What do you think about using microbes in your garden? Do you have any tips, tricks or stories to share?