How to Make Your Own Compost

Worms in your kitchen?

People who want to compost food but fear drawing wildlife into their yards might consider vermicomposting—using worms to convert organic waste into nutrient-rich humus. When done correctly, vermicomposting is odor-free and can be maintained indoors.

Unlike backyard composting, which relies on a biological process to accelerate decomposition, vermicomposting utilizes a digestive process—worms ingesting and excreting organic material. These are not garden-variety earthworms; they are epigeic (waste-eating) redworms available through gardening stores or the Internet.

“The worms eat all your fruit and vegetable scraps,” says Carolyn Mountel, executive director of the Tomten Institute, which specializes in organic recycling and gardening. “Don’t feed them meat, cheese, or oil, though. That’s not their niche. And don’t overfeed—then they will smell.”

The worms live in a shallow bin you can build or buy. To determine what size you’ll need, collect your organic kitchen waste for a week. Weigh it daily and multiply the average daily weight by two. That’s how many pounds of worms you’ll need. Each pound of worms requires one square foot of space. Make bedding from damp shredded newspaper; food goes on the bedding.

The end result, called worm castings, has a neutral pH and looks like coffee grounds. It’s potent—use only a few teaspoons to fertilize your indoor plants.

For more information, visit www.soilfoodweb.com.

Collection questions

If you or anyone in your household is prone to allergies or respiratory ailments, be aware that organic waste collected for your compost bin can produce harmful bacteria and mold.

Researchers at Wageningen University in the Netherlands found accelerated levels of bacterial endotoxins—cell fragments that are released when bacteria die—in households where organic waste, which is moister than mixed garbage, was collected in containers that weren’t emptied for a week or more. Endotoxins can cause coughing, breathlessness, and flu-like symptoms.

If you’re concerned about bacteria and mold levels in your home, be sure to empty organic waste once a week. Also consider storing organic waste in the garage or just outside the back door.