Compost Tea Recipes
As is true of compost, not all compost teas are equal. Teas may vary by bacteria and fungi populations and by nutrient content. Some of this is controlled earlier during the composting process, before brewing compost tea. For instance, to make compost tea with high nitrogen content, you should use finished compost that was created with special attention to nitrogen.
While nutrients are important to plant health, so are the microorganisms that inhabit compost. Although all plants need beneficial bacteria and fungi, some plants prefer different proportions. For instance, long-lived trees, shrubs and perennial plants prefer compost tea recipes that are rich in fungi, while annual plants such as flowers, vegetables and turf grass prefer more bacteria than fungi.
The good news is that the microbe content is easy to control or manipulate during the brewing process. Below, find an outline of techniques to create your own fungal, bacterial and balanced compost teas.
Finished compost is at the heart of every compost tea recipe. Completely finished compost has an earthy, sweet smell, and usually contains both fungi and bacteria. Although worm castings are safe for compost tea brewing, composts that contain animal manure may harbor e-coli bacteria. The tea-making process should kill e-coli, but it’s better to be safe and avoid composts with manure than to take the risk.
Oxygen-loving (aerobic) bacteria will thrive in a compost tea brewer if provided the correct environment. Water should be dechlorinated or the bacteria won’t survive. Oxygen needs to be injected with an air pump to keep beneficial bacteria alive and growing. A small amount of sweet, sugary food, like non-sulfured molasses, maple syrup, cane syrup or even fruit juice, helps bolster bacteria populations. Although all compost contains some amount of bacteria, vermicompost is especially rich in these microbes because bacteria live in worms’ digestive systems.
Fungi, on the other hand, have a tough time competing with bacteria during brewing. In their book Teaming with Microbes, Jeff Lowenfels and Wayne Lewis give some tips to bolster your fungal populations. About one week before brewing, mix your finished compost with a fungi food source like oats (oatmeal, powdered baby oatmeal or oat bran), powdered malt or soybean meal. Add 3-4 tablespoons of fungus food for every cup of compost.
Fungi need moisture to grow. After adding the food source, check to make sure the mixture is damp but not drenched. If you need to add a little moisture, remember to use dechlorinated water. Store the mixture in a dark, warm area – about 80 degrees Fahrenheit would be best, although room temperature should be sufficient. At the end of the week the mixture should be full of fine, silver strands of fungal hyphae.
During brewing, it helps if fungi have some added surface area to grow on. Add some bulky ingredients, such as fruit pulp, rock dust, kelp or fish hydrolysate (basically, ground-up fish), to harbor fungi. Fruit pulp is easily on hand for any juicing fans, and kelp can be bought from many garden centers.