Mm.. Yum! Compost Tea! June 16, 2015 13:34

As a kid, one of my favorite things to do was play with my friends in the sandy ditch along the fence of our school and the neighboring farm. We would dig tunnels and build towers to make elaborate civilizations complete with flowing rivers of brown mucky water. As a full grown human, I’m pretty sure my ten-year-old self still calls the shots a lot of the time because I still love getting my hands into weird brown brew and watching it swirl around.  

Since I am now a real grown-up, I feel like playing in muck needs to be accompanied with some kind of respectable reason (which is a big time consequence of a self-perpetuating and internalized expectation to be civil - meaning forget that! We should play all we want!!). One of my favorite excuses to play with dirt and water is to make compost tea. I like to do this as much as possible for our gardens at home, for friends, and sometimes even just to spray in spots around the city.


Compost tea is pretty much the best when it comes to making a little go a long ways. It increases beneficial bacteria, fungi and other micro-organisms in your soil. You can use different recipes to grow specific kinds of micro-organisms that tailor to your gardens needs. Compost tea can even be brewed to create environments where tiny microbes contribute to filtering out toxins and breaking down contaminants like petroleum.


Like a lot of things, there are right processes to making compost and also some risks when we don't follow them:  

-Not enough air: Without enough oxygen (or any oxygen) your compost will be growing anaerobic bacteria that you definitely do not want, like pathogens and root feeding nematodes. Air and agitation will produce the good bacteria you want to benefit you soil and the the plants in your gardens. To do this, you will need a powerhouse of an aerator (more than just an aquarium pump).  

-Too much Food: Too much food can cause bacteria to overproduce and the tea to go anaerobic. Bacteria are tiny, so no need for a hero-size  meal.  

-Bad Compost: Basically, the biological make-up of your compost will be foundation of your compost tea. And not all compost is created equal. This can be used in your favor, or to your disadvantage. If you know where your compost is coming from, how it’s been decomposing, and for how long, you can make assumptions about what it lives in it - whether there be micro-friends or micro-villains, and whether it be booming with bacteria or dominated by fungi.


There are a lot of opinions about what makes a good compost tea. I know some folks are happy throwing compost in a bucket, mixing it up now and then, and splashing it into their gardens when they feel like it’s a good time. I've known others who break it down to an extremely scientific method that should never be tampered with - which require fairly expensive and super powerful aeration and working within tight slots of time. I'm not a micro-biologist, but I did work for one.

There are some pretty simple DIY techniques to test the soil in your garden and see what kind of microbes are living in there. However, for the sake of the length of this post, we will save that for another time.   From my experience of making compost tea with quite a few different people over the last 3-4 years, this is how I've come to make my Actively Aerated Compost Tea:

1. Dechlorinate 5 gallons of tap water in a clean bucket by letting it sit outside overnight.  

2. In the morning, add the following ingredients in a tight mesh bag (tighter than your

laundry bag, not as tight as a stocking so the fungi will be able to pass through):
-1 handful of worm castings and/or fresh quality compost
-an eyeballed tablespoon of molasses -a splash of fruit juice
-1/4 cup of soaked oats  


3. Throw that into the bucket of water with some:
-bioaccumulating plants ripped up or finely chopped (comfrey, yellow dock, stinging nettle as examples. Be sure to make sure they are collected from safe places, far away from train tracks or chipped paint).
-kelp -duckweed
-a splash of fish emulsion   


4. I put an aerator at the bottom of the bucket with something to weigh it down like air stones or rocks (being sure not to cover the aerator). The aerator should be stronger than an aquarium pump as you need some agitation along with aeration. Personally, I use a pond pump because it costs about a 3rd of the price as a compost tea specific aerator, and because I live in a shared house with 3 suites so the silence of this tool is greatly appreciated by my housemates. (Compost tea specific aerators cost about 150 bones, are loud and make a mess - which is not very accomodating for a lot of people. If it works for you though, I hear this is the most effective system).  

5. In the morning, I turn it on for at least 24 hours up to 36 max. Different lengths of time will grow different micro-organism, and after 36 hours, your tea will start to lose the beneficial ones. I try to time my tea so I can use it right away. That means having it ready for the morning before it gets too hot outside, or in the later evening when the weather starts to cool down. When my tea is ready, I like to use it within 4 hours after which the beneficial aerobic micro-organisms will start to die, but I can use it up to within 48 hours.  

6. 1 gallon of compost tea goes about 1000 sq ft and can be applied to your gardens in soil and on plant leaves once every 2-4 weeks for best results.  

So that’s it! Compost tea! One of my favorite things! Soil rocks, and is the foundation of what we need to live. Plus it’s home to some pretty cool forms of life (like the waterbear - if you don't know about it, google it!). It also happens to be what drives my big time nerdiness.


by Kelsey Cham Corbett
June 16th, 2016