Why You Should Be Using Compost Tea

A frothy, bacterial-rich brew of Actively Aerated Compost Tea

​By: Travis Lesser
​If you have been paying attention to our social media and emails, you have seen a lot about compost tea over the past few weeks. But what exactly is compost tea and why should you care?
 
Basically, compost tea is a solution of compost, ideally vermicompost, non-chlorinated water, and a feedstock such as molasses. But don’t be confused by the name, you don’t want to drink this stuff. It should only be used on your plants.  The main idea is to apply tea as part of a regular regiment to make your soil and your plants healthier and less susceptible to disease. 
 
While tea can be produced in a few different ways, generally speaking, it involves steeping compost into water along with molasses.  Other ingredients can be added, such as kelp meal, but the main idea is to aerate and agitate the water to allow the molasses to spread evenly across the solution.  This allows beneficial microbes that exist in the compost to multiply rapidly by providing ample oxygen and complex sugars. Giving the process approximately 24 hours allows for optimal microbial activity, essentially making your rich vermicompost go farther.
 
People have been using compost tea for ages. You may recall your grandmother using a bucket with an aquarium air stone to make her tea, and spraying the solution onto her plants. Academically speaking, the ultimate goal for applying compost tea is to inoculate the soil with a strong microbial population.
 
While Grandma’s method is effective, one drawback is that anaerobic, or lacking in free oxygen, pockets can be created in the bucket, which can ultimately result in carrying pathogens into your soil.  A better method is called the vortex method.  This is the process used by Cityscape Farm Supply on Compost Tea Tuesdays by using our Cityscape 5-gallon Brewer at The Barn at Lemont.
 
The vortex method ultimately introduces a larger amount of oxygen than the air stone method, agitating the water to a greater degree and therefore creating more movement for the microbes.  Another term for this method is active aeration, and a good term for the end product is Actively Aerated Compost Tea (AACT). By keeping the water moving in this manner, it allows the beneficial bacteria to spread out and multiply at a rapid rate.  A bacterial-rich brew will have a bit of a froth at the top, and will smell earthy and sweet. If it stinks, it has gone anaerobic and you should not use it at that point. 
 
Another key thing to understand about AACT is that it has very little shelf-life. Once the oxygen source is taken away, the beneficial microbes begin to die off.  Therefore, it is best to apply the tea via a foliar spray immediately, or at least with a few hours.  Additionally, benefits from AACT are generally not seen immediately.  A weekly regiment during growing season is best, as you are consistently introducing new and beneficial bacteria into the soil, ultimately creating healthy and resilient plants.
 
I have personally been using compost tea on my garden beds for three years, and can attest to its effectiveness.  As advertised my soil is rich in organic material, producing healthy and prolific plants year after year. I have never applied a pesticide and have only used a small amount of fish fertilizer (mixed in with the tea) once this year.
 
Do you have a compost tea success story? If so, tell us about it in the comments! 

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A state fair-sized zucchini from my garden. July 2017