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. 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 has completed its process, and has sat long enough undisturbed for beneficial bacteria and fungi to grow to acceptable levels. If you do not have an adequate source on hand, compost for brewing tea can be purchased. It is important to obtain testing results for all compost, whether you have made it yourself or are purchasing it. All respectable companies selling compost for tea should be able to provide you with test results. Once purchased or made, your compost can be energized prior to brewing to give your fungi a head start. Fungi take longer to grow, so feeding them early (about 4 days with oats and Fish Hydrolysate) will give you a better chance of having them in your finished tea.
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. Many municipalities are now using chloramines in drinking water, because it is more stable than Chlorine. This can not be agitated out, but can be negated simply buy adding organic matter to your water 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. Here is a great brewer, perfectly sized for the home brewer from Keep It Simple, Inc.
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 (NOT Emulsion!), Soluble Kelp, Humic Acid, Oatmeal (oats), and Organic Flour. It goes without saying that products should be all natural and/or Organic.
We purchase from the following, as we find the quality and service excellent with these vendors ; Neptune’s Harvest, Keep It Simple Inc., and Bob’s Red Mill. A Google search will produce companies in your area if these prove to distant form your location.
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 ICT Organics 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!
Part IV Coming Soon!