In Part I of our series on Compost Tea, we learned of the existence of the Soil Food Web. In Part II we learned about organisms within the Food Web, focusing on four building block organisms that plants use to gather the nutrients they need to survive. Now let’s take a look at actually brewing Compost Tea.

First off, let’s start referring to Compost Tea in the correct manner, Actively Aerated Compost Tea (AACT). This distinction is important in order to differentiate it from other ways of applying organisms to your soil. The AACT process involves feeding and growing organisms under properly oxygenated conditions. If proper oxygen levels are not maintained, then some very bad visitors can show up in your brews. Hence the term “Actively Aerated”. Processes that simply steep compost without foods or aeration are ‘Leachates’ or ‘Extracts’.

Ok, so you have decided that brewing AACT sounds like a great idea, and you would like to try it. Excellent! Simplified, the process involves taking a high quality, well made compost, agitating the organisms from the compost into water, feeding and providing adequate aeration, and waiting for them to multiply.

Keep It Simple 5-gallon Compost Tea Brewing System

You will need the following materials to be successful;

Compost: Remember, in Part I we learned that not all compost is equal, and what some people consider compost, is not really compost at all. For our process, we are looking for a rich dark brown (think coffee grounds color) finished material, alive with organisms, free from pathogens and weed seeds. Finished meaning the compost had completed its process, and has sat long enough undisturbed for beneficial bacteria and fungi to grow to acceptable levels. Compost can be energized prior to brewing.

Water: You will need a chlorine free source, or if need be you will need to remove the chlorine. Chlorine being highly unstable, can be released from water by agitation for a period prior to brewing.

Brewing Container: AACT can be brewed in containers ranging from a five gallon pail up to large tanks holding thousands of gallons. You will applying your tea at a rate of about one half gallon per 1000 square feet of soil, so plan accordingly.

Source of Aeration: maintaining oxygen levels above 6 parts per million is essential in growing the aerobic organisms we are looking for. For small brewers, an aquarium pump can be used, while for large brewers, as we have (250 gallons), a regenerative blower will be necessary.

A mesh bag: This is an optional item. The amount of compost used in relation to the amount of water is small, so it allows the brewer to use a mesh sack to contain the compost, making it easier to spray the tea, and simplifying the cleaning process. You may also choose to let the compost hang free in suspension, but you will need enough agitation from your aerator to help dislodge the organisms from the compost.

Food for the Organisms: Depending on which organisms you will be trying to grow, you will use a combination of the following food sources; Fish Hydrolysate, Soluble Kelp, Humic Acid, Oatmeal (oats),  and Organic  Flour. It goes without saying that products should be all natural and/or Organic.

24 hours: What? Yes 24 hours, for that is the average time it takes for the organisms to consume all the foods and multiply into finished Actively Aerated Compost Tea.

Now, if you’ve gotten this far and thought, WHOA!! this is getting to complicated, take a deep breath, making AACT is not as complicated as it sounds. If you find yourself still overwhelmed, take a look at these 2 products. They are pre-brewed AACT in a dormant state, with a shelf life of about one year, ready to be applied to your lawn or garden.

They are ‘1-2-3 Compost Tea’ and ‘Natures Solution Compost Tea’. Both are produced by companies well versed in the production of Compost Tea, and both effective products.

For those of you still interested in brewing your own tea (and I hope there are a few of you left), tune in next time, for a discussion of the process and application methods.

Thanks for hanging in through a long series,

Scott

www.blueheronlandscapes.com

In Part I of our series on Compost Tea, we had a brief discussion on the Soil Food Web and compost. We learned that these are tools we can use to restore the biology to our soils. Now would be a good time to talk about the microorganisms within the Soil Food Web, their roles, and then we can move on to brewing compost tea.

Healthy biologically active soil is home to billions and billions of microorganisms, and the four that represent building blocks for healthy soil are Bacteria, Fungi, Nematodes, and Protozoa. One teaspoon of healthy garden soil can contain up to a billion bacteria, yards of fungal hyphae, thousands of protozoa, and dozens of nematodes. Truly an incredible amount of life, all invisible to the naked eye, simply living and going about their daily routines. Let’s take a quick look at each group.

Bacteria are tiny, one-celled organisms and fall into four functional groups; Decomposers, Mutualists, Pathogens, and Lithotrophs. We are most concerned with Decomposers (which break down materials) and Mutualists (which form symbiotic relationships with plants), and want to avoid Pathogens (the bad guys) for obvious reasons.

Ciliate next to bacteria (long black line) amidst small bacteria cells and yeast cells. 500x magnification

Fungi are microscopic cells that grow as long threads or strands called hyphae, which push their way between soil particles, roots, and rocks. Fungi perform important services related to water dynamics, nutrient cycling, and disease suppression.

Nematodes are non-segmented worms typically 1/500 of an inch (50 µm) in diameter and 1/20 of an inch (1 mm) in length. Nematodes mineralize, or release nutrients in plant-available forms.

Ciliates seen at 500x magnification

Protozoa are single-celled animals and are classified into three groups: Ciliates, Amoebae and Flagellates. Protozoa play an important role in mineralizing nutrients, making them available for use by plants and other soil organisms.

(Information provided from papers written by Dr. Elaine Ingham, Soil Foodweb Oregon LLC. Pictures captured from “Compost, Soil & Compost Tea Organisms” DVD, Available at www.microbeorganics.com )

Still with me? Good.

Bacteria and Fungi are the holder of nutrients, and nematodes and protozoa are the releasers of nutrients. In short, the nematodes and protozoa eat the bacteria and fungi, and poop out nutrient rich material. Always comes back around to manure, doesn’t it?

Growing and re-establishing these organisms in poor soils is essential to re-energizing the Soil Food Web. The numbers present and needed of each of these groups of organisms differs, depending on the existing soil ecosystem, and the type of crop one intends to grow. Perennial plant ecosystems (forest, tree and shrub landscapes and perennials) are generally fungal, while annual plant ecosystems (annuals and vegetables) are generally bacterial. Grass ecosystems (great plains, lawns and turf) tend to be slightly bacterial. These compositions are important to note whether making compost, steeping Leachate or brewing Compost Tea. By building the correct soil organism communities, we provide plants an environment they can easily exploit, giving them the best opportunity to thrive. This is the essence of the organic process.

You may be asking, “How can a plant exploit?” Great question. Plants actually attract beneficial microorganisms. Say what? That’s right, plants, by releasing nutrients called exudates through their root walls into the rhizosphere (an area of only a couple of millimeters wide surrounding the root), attract the organisms they need to survive. The exudates attract bacteria and fungi that will in turn supply the plant with the nutrients it needs. Pretty cool eh? The plant actually attracts and feeds the certain bacteria and fungi that produce, or help the plant find the nutrients it needs to survive. It’s gardening on a microscopic level.

You now have a very basic understanding of the Soil Food Web. As with any complex subject, it can not adequately be covered in short blog posts. I will be providing you with suggested reading material and reference links at the end of the series.

In part III we will look at the brewing process.

All the best,

Scott

www.blueheronlandscapes.com