Brewing Aerobic Worm Tea

A few years ago, we bought a SoilSoup Bio-Blender and a Worm-a-Roo earthworm composting system so that we could make compost tea to feed our plants.

Worms (and the associated microbes that accompany them) are responsible for turning organic scraps into compost. Worm castings are particularly prized for their beneficial effects on plants. Aerobic worm tea extracts the microbes from the worm castings into solution and encourages them to multiply, effectively creating more compost.

Here's how we make it

We bought an 18-gallon laundry tub from Wal-Mart that holds the Bio-Blender and "tea bag" perfectly. We fill the tub with about 15 gallons of water from the hose and add fertilizer to make a 1/3-recommended-strength fertilizer solution. For us, that's either a cup of Sea-Plus, or 5 scoops of Miracle-Gro for Tomatoes (or similar from another company), or half of each. Then we turn on the Bio-Blender (which is really just a high-powered bubbler) to start aeration.

The tea-bag is a long, narrow pouch made of a porous synthetic material. In it, we put 4 cups of finished worm castings, 1 cup of dried molasses (from the feed store), and a half cup of corn meal (the kind from the grocery store, not de-germinated). Then we hold it over the tub, dip some of the solution with a pitcher, and pour it into the bag to start carrying the "good stuff" into the solution. Then we hang the bag on the inside of the tub and let it churn for 30-40 hours, depending upon ambient temperature (it takes longer when it's cold outside).

The mixture eventually forms a bubbly "head" like a root beer float, the solution gets warm, and a fair amount of goo clings to everything in the tub. That is all evidence that there are plenty of microbes, so it's time to apply.

First, I filter some of the tea through a bit of loose row cover into a pump-up sprayer. Next, I disassemble the unit and use the worm tea to wash off all the goo. I return the dregs from the tea bag to the active side of the worm bin (they go ga-ga over it and wallow around in it), then wash the bag out in the worm tea, too. Then, we fill gallon milk jugs with the tea and water whatever needs fertilized and use the sprayer to foliar-feed.

The only things we've discovered don't care for it as a foliar feed are legumes, notably limas and snap beans. It negatively affects their leaves for some reason, so those we just feed the root area on occasion, if we can get to it without wetting the foliage.