Life is a miracle and cultivating plants is part of that miracle. In caring for our plants we form a symbiotic relationship with them. We watch our plants grow and do everything we can to help them reach their full potential. When we harvest and consume our crops, those same plants we cared for help us to grow! Seasoned gardeners are aware that this is just one relationship, one link in the miraculous chain of life. It’s so marvelous that many beginner gardeners focus exclusively on that ‘link’ – maybe because it’s the one that happens to be most directly appreciable to our senses. But there is a whole universe right beneath our noses that exists just beyond our powers of vision. It is a hidden world of microbiology that exists in the soil itself. We tend to appreciate this indirectly through effects, rather than causes, observing a plant as “healthy” or “diseased.” But with a little knowledge, seasoned with some imagination (or a powerful microscope!) the true extent to which we share this world can be revealed and the way in which we care for our plants is transformed.

A World In A Teaspoon

Okay, enough romantic talk of Mother Nature. Let’s move on to some mind-blowing facts. And these facts really are mind-blowing! Don’t just “uhuh” as you read these. See if you can actually visualize what is about to be described:

Imagine taking a teaspoon and dipping it into some living soil. Lift it up and hold it in front of you. What do you see? A teaspoon of dirt?

A teaspoon of living soil contains 100 million to 1 billion bacteria, 1 to 40 miles of fungal hyphae, and 1,000-100,000 protozoa!

40 miles of fungal hyphae in one teaspoon!? Now do you see we’re talking about another world within our world? What are these organisms? Well, they are all part of this whole chain of life that helps to grow your plants. These organisms are as real as they are small. And in their huge numbers, they play a really important role in plant health and growth. The bacteria eat the exudates (simple sugars, carbons, carbohydrates) that the plant puts out through its roots, which are then eaten by the protozoa. What is excreted by the protozoa is now plant-available nutrients. Beneficial fungi protect the plant from pathogens and harmful microbes, as well as creating pathways in the soil that bring water and nutrients back to the plant from larger distances. Bacteria and fungi work together in decomposing organic material and making the nutrients plant-available. This is a sustainable process known as “nutrient cycling” that allows for the growth of healthy plants, without the need for fertilizers, pesticides, and other chemicals. After all, there’s no one out there putting Miracle-Gro on our rainforests each year, yet look at how successful plants are at growing in these microbial-rich environments!

The War on Terra

Most soil these days lacks the biology necessary to cycle nutrients to the plant and protect it. Where did they go? They were killed off by so-called modern agricultural methods or “the war on terra” – years of abuse including overuse of synthetic fertilizers, pesticides, fungicides, over-tilling, and compaction.

Chemical fertilizers and other -cides contain salts. Remember back to high school science where you learned about the process of osmosis? It’s the movement of water through a cell membrane from a solution of low solute concentration to a solution with high solute concentration. In living soil, water is locked up in the cells of the microorganisms. With the proper biology in place, you can cut back on your watering by up to 30%! When salts in the form of chemical inputs are added to the soil, the water is drawn out of the microbes and they are either killed or go into a dormant state. Now the plant is dependent on you to provide all of its food and protection. That’s why you have to fertilize on a regular basis.

In addition to damaging the biology in the soils, these chemicals are having other impacts of much greater consequence. Nitrates from fertilizers are leaching into our water system, and pesticide exposure has been linked to a variety of serious diseases such as cancer. There’s a reason that lawn companies recommend keeping children and pets off lawns after they’ve been sprayed. These chemicals are highly toxic!

So what’s the alternative? There is a shift from our current N-P-K paradigm towards an organic way of gardening by feeding the microbes in the soil and letting them do the work for us. Our ancient ancestors gardened in this manner long before we knew what bacteria were! Fertilizer was in the form of manures, which were decomposed by the microbes and provided all the nutrients the plant needed.

Creating Life in Soil Again: Compost Tea

Using present day technology, we are now able to add these beneficial organisms back into our soils and feed them through a variety of organic inputs. The three best things you can do for your soil is to top dress with compost, mulches, and compost tea. Since many of you probably already know about the benefits of compost and mulch, I’d like to focus a bit more on compost tea.

When I say compost tea, I’m referring to actively aerated compost tea, or AACT for short. This distinction is important because there is a big difference between throwing some compost or manure in a bucket and letting it sit for a couple of weeks, and AACT.

AACT is an aerobic water solution that has extracted the microbe population from compost along with its nutrients. The concept behind compost tea is quite simple, though the actual process becomes scientific and has many variables that need to be accounted for. The idea is that compost (full of beneficial microorganisms) is put into water and then nutrients or foods for the microorganisms are added to allow the bacteria and protozoa to multiply rapidly and the fungi to grow. Air is sent through the water to keep the dissolved oxygen levels above 6 mg/liter, as this selects for the aerobic microorganisms, which are the ones found to be most beneficial. At the end of the brewing cycle, what you have is a concentrated liquid literally teeming with billions of microorganisms that can be sprayed directly onto the leaf surface of your plants or onto your soil. This puts the “good” biology where the plant needs it to protect itself. It keeps the plant healthier and helps to fight off potential diseases. The “good” biology occupies the infection sites on the leaf surface and survives by consuming the exudates that the plant puts out. The “good” biology then out-competes the pathogens for the space on the leaf surface or around the roots (rhizosphere). This is how plants protect themselves and thrive in nature.

It is possible to make bad AACT. If you don’t start with good compost, don’t add the proper amount of nutrients, or keep the brew sufficiently aerated, you could be selecting for pathogens rather than beneficial microbes and end up with a tea that will have little to no effect on your plant or possibly even do damage.

Along with compost tea it’s important to do applications of other bio-amendments such as soluble seaweed, humic acids, and fish hydrolysate, for example. Seaweed serves as a bacterial food substrate and also provides additional benefits for your plants in the form of growth hormones, increased stress resistance, and faster plant response. Humic acids serve as a fungal food, and also chelate (bond with) minerals in your soil and make them available (many minerals in your soils are “locked up” or unavailable). These sorts of applications work by feeding the microbes, which in turn feed your plants.

When gardening in this manner, it’s important to adjust your application rates or program to fit within the needs of your garden. I’d suggest an initial topdressing of your garden with compost and an application of compost tea, adding soluble seaweed and humic acids to the tea after brewing. Then, another application 2-3 weeks before planting and another one when you plant your starters (adding mycorrhizal fungi into the hole at this time). In the fall, I’d add a mulch to your garden, followed by an application of compost tea (to speed up decomposition over the winter). You may or may not need an organic fertilizer (NPK below 10-10-10) to supplement the rest of your program.

Once an organic program has been established, typical application rates of AACT, humic acids, and seaweed are only 3-5 times per year. Now the plant is in charge, and the organisms are in place to cycle the nutrients for the plant. This is what sustainable gardening is all about!

WORDS: Tad Hussey, Keep It Simple, Inc. www.simplici-tea.com

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?