Making Compost Tea in a Rain Barrel

First off, rain barrels. There are many good reasons to catch rain. Water is useful, obviously. It also costs money. Rainwater can be used for many things, and of course, its totally free. Gutters that are currently used to divert water away from things can simply be used to divert water into catchment systems. We have friends that live without city water, living off rain water, caught from roofs and purified with simple countertop water filters. They have water when there's a drought, and they have water when the water line bursts and the rest of us are waiting for the city to fix it! They have fairly developed, clean, reliable systems. Ours is rudimentary.

I like to use rainwater in gardens as a substitute for using tap water. (Tap water contains chlorine, which is toxic to many soil microbes.) I also like the idea of building ponds to create places for frogs and fish. The permaculturalists remind us that water is moving through the land, so why not play with it a little as it passes by? Why not use it, store it, purify it, grow things with it, grow things in it. . .

Below is a pic of our first, simple rain barrel that Sean and I built last year. Its made from a 55 gallon plastic drum with the top cut off of it. The gutter simply empties into it at the top. At the bottom of the barrel is a fixture that has a garden hose attached, so we can water the garden out of the barrel when it is full. At the top of the barrel, the black tube is fixed and serves as an overflow. When it rains, the barrel fills up quickly, and the overflow is diverted to a pond in the garden and to other barrels for more storage and garden watering. (We have had to attach a screen to filter the debris from the water coming from the roof...)

It works well in the summer. In the winter, the water freezes and becomes a massive block of ice. Its not a terrible problem, but it could potentially burst some of the fixtures...

The overflow pond, just after being installed last year:


Secondly: Why compost tea? Compost (and/or manure) tea is a way to fertilize soils and plants. If watered with it, the soil and plant roots are given a good serving of nutrients, and if sprayed on, the leaves of plants can also be feed, called "foliar feeding". If compost tea is allowed to brew for a day or two, the beneficial microbes in composts (fungi and bacteria) can proliferate and then be spread into your gardens. Some people even "feed" compost tea molasses so that the microbes will populate quickly.


So here's how we do it: a simple bamboo frame is constructed that sets on top of our rain barrel. An old pillow case is filled with composts and manures, tied at the top and hung from the frame. Its basically like we are making a massive cup of tea, hence the name. It sits like this, brewing, for 1-3 days before we use it. You can do smaller batches in 5 gallon barrels in the same manner.

When I walk by, I like to take an old bamboo pole and stir/swish the water around. It helps mix the compost and tea in with the water as well as introduce oxygen to the brew, which helps good microbes grow. When we are ready to use it, we simply open the garden hose at the bottom of the barrel, and fill up our watering cans. If I am going to spray the tea onto plants or land, in a backpack sprayer, I'll attach a small piece of cloth over the end of the hose to filter out any debris, so the sprayer doesn't get clogged.

There's a massive amount of effort that people are putting into developing compost tea brewing and application methods that you can read about. For now, we keep it simple, but you are free, of course, to get crazy with it!