Brewing Compost Tea

Organic gardeners everywhere understand the value of compost. Compost has no equal as a power food and soil modifier. But what about compost tea? If you’ve still not tried compost tea, you are in for a real awakening. The good things you’ve read or heard are true… compost tea really is the secret juice you’ve been longing for! A couple of applications of compost tea and your plants will leap out of their beds to thank you. OK.. that’s overstating it a bit but you WILL become a convert for life!

How Compost Teas Work

Taking on board the actual goal of brewing compost tea will give you the most insight into why compost tea works so well and I think it will make you a better gardener. So lets go…

Around us everywhere, but invisible, is a microscopic web of life (and death). They’re on our skin, in soil, on plant leaves and even dirty kitchen benchtops! On any organic surface you can name, you can be absolutely sure there’s an entire colony of invisible creatures, living and dying, eating and being eaten, processing nutrients, converting sugars and playing their role in the ecosystem. Amazingly, just one handful of healthy soil is home to a mind-boggling 8,000 species of fungi and 15,000 species of bacteria as well as a variety of nematodes and protozoa, numbering in the billions. Some fungis are good. Some are bad. Some bacteria help while some cause trouble. 

The aim of compost tea brewing is to “farm” the beneficial bacteria and fungi in order to inoculate the leaves of plants or soil with the beneficial species. Creating compost and digging it into our garden is the traditional means of treating soils in order to cause an explosion of beneficial micro-organisms in the root zone. The brewer of compost tea is just extending the process and speeding up the population growth, creating a liquid which can be used as a foliar spray to inoculate the leaves as well. Brewing a tea also allows us to make a small quantity of mature, well finished compost go a lot further.

Brewing Compost Tea

Compost tea is created by steeping (soaking) a quantity of mature, well finished compost in aerated water. Aeration is vital, the beneficial bacteria we need are aerobic and require oxygen to thrive. Molasses is added to feed the good bacteria to speed-up their population growth.
There are numerous different compost tea recipes and techniques documented and available online but here’s a basic outline…

Hardware You’ll Need:

A 5 gallon bucket
A reasonable quality aquarium air pump able to run 3 “air stones” or bubblers.
Three air stones, several feet of air tube and a gang valve to evenly distrubute air to the bubblers.
One fabric bag for straining the solids out of the tea – an old pillowcase is suggested

The Method:

Arrange the three air stones, spacing equally, on the bottom of the bucket
Add mature compost to the bucket to around one third of it’s capacity
Top up with clean potable water free from chlorine to within 2 inches of the top
Start the pump and aeration process
Add 1 oz of unsulfered molasses and stir through the mixture
Gently stir the mixture a few times a day taking care not to move the bubblers
After 2 but no more than 3 days strain off the liquid and immediately apply to plants; you can use it as either a foliar spray or a soil drench around plant roots.

Important Points For Brewing Compost Teas

It’s important to only use mature compost that you can be confident has no pathogens remaining. The molasses will also feed pathogens like E. Coli and cause rapid growth in their population, making the tea a risk to your health. The compost you use, ideally, will have reached and maintained a temperature of 150 degrees F for 3 days during the composting process in order to eliminate pathogens. The high quality compost that you get from automatic kitchen composters like the NatureMill or worm compost bins is best for brewing compost tea.

Using compost tea is an easy way to dramatically improve your gardening results. Become a compost tea brewer today and watch your garden bloom!