Worm Tea

Worms are easy to forget about, and they don’t mind a little neglect – they require feeding infrequently and prefer to be left alone in the dark. In fact, too much food can cause moisture and pest problems. They’re quiet. They’re calm. It’s fun to watch them wriggle about when their bin’s lid opens, casting bright light into their otherwise dark world. Peter V. Fossel, author of Organic Farming: Everything You Need to Know,  sheds some light on the magic that is vermicomposting – or composting with worms.

Worm castings have been long known to be a highly fertile component of organic soil. Compared to average soil, worm castings are said to contain 5 times more nitrogen, 7 times more phosphorus and 11 times more potassium. They are rich in humic acids and improve the structure of the soil as well.

Unfortunately, the castings are rather difficult to harvest without also harvesting baby worms and worm eggs. Nor could it be called a tidy enterprise. What’s more, vermin-composting bins available from mail order sources can cost $100 or more, and that’s for a small-scale backyard garden operation.

We get around these limitations by harvesting, not the castings, but what I call the “worm tea” that results from a vermicomposting system. We use this as a foliar feed, and the results have been remarkable. Here is how our system works:

composting with worms

Organic Farming: Everything You Need to Know

This system amounts to feeding worms your kitchen scraps in an enclosed bin, and harvesting their castings for use as organic fertilizer.

  1. Start with several 10-gallon plastic storage tubs with lids. Drill a dozen ½ inch holes in the lid, then cover it with window screening held in place with adhesive caulk. On the bottom of the tub, at one end, drill another 10 or so holes for drainage. Cover this with screening to keep the worms from getting out. Suspend the tubs on a shelf about 16 inches off the ground, held up with concrete blocks.
  2. Drill a 5/8 inch hole in the top of a gallon milk container. Into this, slide a piece of 5/8 inch (outside diameter) hollow tubing. A plastic funnel fits into the top end of the tube and this whole thing should be set under the tub’s drain holes.
  3. Now fill each tub about ¾ full with rotting straw, partially rotted leaves, hay, shredded cardboard, or even shredded newspaper. Wet the material down well until it’s fully damp, then place in each tub 500 or so red wiggler worms (Eisenia foetida), which are ideally suited to life in a worm bin.
  4. Start adding kitchen scraps, placed under a layer of bedding. Virtually any fruit or vegetable scrap is fine, along with eggshells and coffee grounds. Avoid meat and fatty foods. Start with small amounts of scraps, then increase the feedings as the worms grow and multiply. There are no hard rules; use your judgment.
  5. Within a few weeks, dark brown worm juice begins to fill the empty milk jugs. I used this as a transplant solution at first in our organic vegetable beds and it seemed to work quite well, diluted by about a ½ cup per gallon of water. Every few weeks I simply harvest the juice and let the milk jugs fill again.
  6. Within a few months, you should be able to take half the bedding and worms out of a tub and start a new tub. Worms don’t like their own castings, so they’ll begin to die off if you don’t transfer some.

composting with worms_pile

Organic Farming: Everything You Need to Know

Large compost piles with aged manure ready for the farm’s large fields can take many months, a year or more to break down completely.

Worms love tea bags, carrot shavings and soggy spinach leaves. They’re perfect for anyone who cooks, wants to reduce waste, and needs organic fertilizer.