If you would like to compost your food scraps but don’t have space for an outdoor compost pile, worm farming or vermiculture may be right for you. A worm farm is a contained, indoor compost bin for food scraps. It uses compost worms to break down food waste and produce worm casting.
Worm casting, also called black gold, is the waste that worms produce after eating food waste and is a wonderful fertilizer. Worm castings can be used in vegetable gardens, flower beds, and potted plants.
While the earthworms we find in the garden do break down organic matter, they are not the right worms for your worm farm. Red Wigglers or Redworms live on the soil surface, can eat up their own body weight in food per day, and are best for home worm farms. They can be ordered online or found at a bait shop.
What to feed your worms
A diverse selection of food scraps is best for the worms. Cut food into smaller pieces for easier feeding.
Best: non-citrus fruit, vegetables, eggshells, bread, and tea bags.
Good (use sparingly): citrus fruit, coffee grounds, onions.
Bad: meat, fish, eggs, dairy, processed food.
Most worm farms will have two layers; the lower layer collects the liquid from the composting process and the upper tray is where the worms live, and the food scraps are added. If the holes in the upper tray are large enough for the worms to fall through, add a screen at the bottom of the tray.
In the upper tray add a layer of damp shredded newspaper, the newspaper should be as damp as a wet sponge. Add some food scraps to the top of the shredded newspaper and then add the worms. They will bury themselves in the food scraps and newspaper. Lay a few sheets of wet newspaper over the top and tuck in the corners.
The first few weeks the worms will be getting used to their new home and you won’t see much happening. Once they get going, they will eat up to their own weight in food every day. This means that, if you have one pound of worms, you will need to add one pound of food scraps per day.
Add more damp, shredded newspaper onto food scraps to reduce smells. If your worm farm starts to smell bad, you may be overfeeding the worms. Remove any rotting food from the tray and reduce the amount of food that is added each day.
The worm castings will be ready to harvest every 4-6 months, will be dark brown, and the texture of coffee grounds. Add food to one side of the bin to attract the worms to that side in a few days and scoop out worm castings from the other side of the bin. The liquid in the bottom tray can be drained out the bottom of the worm farm occasionally. It can be diluted as one part worm farm liquid to seven parts water and used as a plant fertilizer.
Going on vacation? No need to worry, worms can survive for 4 weeks without feeding.