Compost worms offer a simple and cost-effective way to make your own fertilizer using common waste materials from your own kitchen!
Vermicomposting uses worms – ideally, red wigglers – to create a mixture of decomposing vegetable or food waste, bedding materials, and vermicast.
Vermicast – worm “castings” or worm manure – is the end product of the breakdown of organic matter, and contains a higher saturation of nutrients than the organic materials had prior to vermicomposting.
The final vermicompost mixture that results from this entire process contains water-soluble nutrients, and is an excellent, nutrient-rich organic fertilizer and soil conditioner.
All you need to get started are:
- Worms, Worms, Worms – The best worms for composting are red wigglers. Unlike typical earthworms found in the soil, epigeic worms like red wigglers live in decaying organic matter (not soil), and thrive in the confined environment of a compost bin. They reproduce quickly and have huge appetites, consuming more than their own weight in food every day. One pound of compost worms (about 1,000) is all you need to get started.
- A Compost Bin – For a simple, compact, all-inclusive composting system, we recommend the Worm Factory 360. However, you can also make your own compost worm bin from a washtub, dishpan, plastic storage bin, or similar container. The basic requirements are that it be 8-16” deep, have a lid to keep out flies and other intruders, and holes in the bottom (1/4” or smaller) for ventilation and drainage. Worms, like humans, prefer moderate temperatures (55-75F), so place your bin in a cool, sheltered area where it won’t freeze or get too hot, like the garage or basement, a shady patio or porch, or even in the corner of your kitchen or laundry room.
- Bedding – The Worm Factory 360 includes starter bedding, but if you prefer to go the DIY route, start with a layer of peat moss or coir (coconut fiber) to lighten the bedding and absorb excess moisture, then add a layer of black and white newspaper, torn into 1” strips. You can add a handful or so of crushed eggshells or powdered limestone to provide calcium and reduce acidity, and a handful or two of garden soil for grit. Keep the bedding damp, but never wet or soggy.
- Food – Worms prefer a healthy, mainly vegan, diet. A pound of compost worms can eat up to half a pound of food per day, but start off slowly, feeding your new worms a little at a time. Food should be chopped into smaller pieces. Bury it into the bedding, rotating around the bin as you go. Do feed: vegetable scraps; fruit peelings/apple cores/banana peels; non-greasy leftovers; plain bread/pasta/rice; coffee grounds/filters/teabags; well-crushed eggshells; shredded paper; dryer lint. Don’t feed: meat & bones; dairy products; greasy foods or fats such as salad dressing or olive oil; very spicy foods/hot peppers; citrus fruits; onions/garlic (OK in small amounts); dog/cat feces; glossy magazine-type paper; twigs & branches.
Harvesting and Using Your Compost
You should harvest your finished worm compost and add fresh bedding at least twice a year to keep your worms happy & healthy. In a stacking bin system, like the Worm Factory 360, harvest the bottom tray, since most of the worms will have left. If any worms remain, put the tray on top of the stack with the lid off; they should head below to avoid light exposure. In a single-layer system, once your bin starts to fill up with castings, limit feeding to only one corner of the bin. An apple core or yummy melon rind should also work to lure the worms to that corner.
To use your compost, you can:
- Apply a 1-inch layer of compost mulch around plants, making sure not to pile it against plant stems.
- Apply 1/2” to 2”over garden soil and mix in before planting.
- Mix into the bottom of transplanting holes and seeding trenches.
- Sprinkle around the base of houseplants.
- Add a little to water for compost tea.