A Step-by-Step Guide to Vermicomposting

All you need to know to start composting with worms, including constructing a wooden worm bin, adding worms, compost bin maintenance, and using vermicompost.

| July/August 1983

My kitchen trash used to smell awful! Coffee grounds, banana peels, lettuce leaves, onion trimmings, orange peels, and plate scrapings all joined with an accumulation of papers, cans, plastic wraps, jars, and bottle caps to produce an unpleasant—and unusable—collection of refuse. Although I emptied the trash can frequently to reduce the odor in the kitchen, I had to hold my breath when I did! 

But no longer! I've now solved my problem entirely with the help of Eisenia foetida, the common red wiggler (or brandling) worm. That's right, worms eat my garbage! What's more, they convert it to black, earthy-smelling, nutrient-rich humus that I use to grow delicious garden vegetables and beautiful houseplants. Operating an indoor worm-powered waste converter is easy, convenient, environmentally sound, and inexpensive. It's fun, too. Anyone can do it, and here's how. 

Basics of Vermicomposting 

The essential components of a home vermicomposting unit ("vermi" = worm) are an aerated container, some moist bedding, and a few thousand red worms. Because you'll be working with a dynamic process, you'll need to carry out certain maintenance procedures both to keep the worm population healthy and to obtain and utilize the end product. These tasks are scarcely demanding: Set your vegetable waste aside in a small container when preparing meals or cleaning up afterward, feed it to the worms once or twice a week, and every few months or so, remove the vermicompost and put the worms in fresh bedding.   

To determine the size of your worm bin, keep track of the amount of kitchen waste you throw away for a couple of weeks. Use a small bucket or can, and collect such discards as potato peels, citrus rinds, greens, leftover vegetables, eggshells, and bread, just about any non meat food residues from your kitchen. Weigh your container to get the average number of pounds per week, then size the vermicomposter accordingly. Your worm bin should provide approximately one square foot of surface for every pound of garbage you'll bury each week. For example, the 8" × 2' × 2' box described here will handle about 4 pounds per week. This bin will be adequate for many one- or two-person households. Another common size is a 1' × 2' × 3' box, which will accommodate about 6 to 6-1/2 pounds of garbage. Aeration is important, and since red worms tend to be surface feeders rather than deep burrowers, a shallow bin with a large surface area is preferable to one that's tall and deep. 

Build a Worm Bin

For an 8" × 2' × 2' bin servicing a two-person household, you'll need the following materials: four 8" × 23 3/8" pieces of 5/8" CDX plywood, one 24" × 24" piece of 5/8" CDX plywood, a hammer, a drill with a 1/2" bit, and thirty-six 6d flooring or pallet nails. (These nails have spiraled flutes on their shanks that increase their holding power, a particularly important quality for wood that'll be both damp and dry.) 

Alternate the overlap on the sides, and put the box together with three or four nails per side. Hammer the bottom on, then drill nine 1/2" holes in the base for aeration and drainage, and set the bin on blocks, legs, or casters to allow air to circulate underneath. Although the worms rarely crawl out of the holes, small amounts of bedding or worm casts will drop out, so you'll probably want to place a sheet of plastic or a tray underneath the box when it's in its final location. 

9/13/2017 2:08:19 AM

I have my bin on the north side of my house, outside Austin. It's mostly shaded & when it hits mid 90's, I take the lid all the way off or leave it askew. They've done fine. When it's over 100, I put a chunk of ice on the bedding that I made in a yogurt container. The only issue I had was with a sudden rain shower.

3/24/2016 5:38:32 PM

For Deidre: the plastic won't kill them if they are not in the sun, but there needs to be some air in the bin so make sure it does not cover them completely. For Al: red worms are fine for indoor composting anywhere, actually. They don't like to be above 100 degrees, since they are made of water mostly. However even when it is 100 outside, if your bin is indoors it is generally much cooler. I highly recommend the book THE BEST PLACE FOR GARBAGE for learning about worms. Appelhof's book (the author of this article) is good, but very dated and incomplete for some things. The book I recommend answers all the unanswered questions in Appelhofs book and then some.

3/24/2016 7:08:05 AM

With Florida's heat and humidity, I worry that covering the bin with black plastic will cook the worms. Do you have advice for me? Thanks. Deidre

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