Vermiculture Composting Produces Humus for the Organic Garden

Organic gardeners know the importance of using compost in the landscape, but not everyone has the space to accommodate a traditional compost bin. Using a vermiculture bin is an option that allows anyone, even apartment dwellers, to create compost from kitchen scraps. Gardeners can use this chemical-free compost as mulch, soil amendment, or as a seed starting medium.

What is Vermiculture?

Vermiculture is the practice of raising worms to harvest their castings, a byproduct of their digestion. Vermiculture composting can take place in an area the size of a 30-gallon plastic tub, or it can comprise a large commercial operation that produces castings for sale in nurseries or to use on an organic farm.

Starting a Worm Compost Bin

Gardeners can purchase a commercial vermiculture bin, or they can start a worm-composting bin in a large plastic tub with a tightly fitting lid. If using a homemade bin, it’s important to punch several small holes in the lid and sides for ventilation. These holes should be smaller than the diameter of the worms to prevent escapees.

The most important aspect of vermiculture is using the right kind of worm. Earthworms from the garden, or night crawlers, are not suitable for worm composting. Only red wiggler worms can live in a composting worm bin. Beginners can start with 1000 worms, which will eat about ½ pound of kitchen scraps each day.

No special bedding is required for a worm bin; shredded newspaper works well. The bedding must be consistently moist, the same as a wrung-out sponge would feel. Be sure to protect red worms from temperature extremes. Most people find that keeping the bin indoors promotes faster worm casting production, while deterring pests.

Vermiculture Problems

Some gardeners are concerned about the possibility of odors coming from the worm compost bin. A healthy vermiculture bin will be odorless. Odors can stem from the gardener adding more kitchen scraps than the worms can eat in a few days, leading to rotting produce. Gardeners must also avoid adding any scraps containing meat or grease to the worm bin.

Aging fruit and vegetable scraps can attract unwanted tenants to the worm bin, including ants and fruit flies. The best way to deter worm bin pests is to bury the kitchen scraps under the worms’ bedding. Gardeners can place cotton balls saturated with mint extract outside the worm bin to deter ants, or they can use a natural fruit fly trap containing vinegar to trap fruit flies before the enter the bin.

Harvesting Worm Compost

An advantage of using a commercial vermiculture bin with multiple levels is the ease of harvesting the finished compost. Gardeners add fresh scraps and bedding to the upper layers of the bin, and the worms migrate upwards as they finish the scraps in the lower levels. Gardeners simply scoop out the finished compost from the lowest bin, and shuffle the empty bin back to the top level.

Gardeners with a single compartment bin must take greater care not to remove too many worms during the harvesting process. Red wigglers can’t live in garden soil, so any worms that are moved into the soil will perish. When the kitchen scraps in the worm bin look more like dirt than stalks and stems, the gardener can push the old bedding and broken down scraps to one side. Add fresh bedding and scraps to the other side, and wait several days for the worms to migrate to that area. It is then safe to remove the finished compost.

Source:

Washington State University County Extension