Temperature for Worm Composting

Conditions for Vermicomposting

• Worms work best at temperatures between 59 and 77 degrees Fahrenheit, in a moist environment. Achieve this by placing the worm bin in a cool, shaded outdoor location, covered from rain and extreme heat or sun. Worm bins may also be kept inside, as they are virtually odorless if properly maintained. A new worm bin should be started with a 2-inch layer of damp bedding (shredded paper, compost, or peat moss), a shovelful of garden soil, some food scraps and worms.

Vermicomposting Inputs

• Worms eat almost any plant or animal product. Raw fruit and vegetable scraps are the best additions to the bin, as well as egg shells, plain bread and pasta, coffee grounds and even dryer lint. Animal products and fats take longer to break down, and therefore tend to cause odor problems and attract unwanted pests. Meats, dairy products, oils, and anything cooked in butter or oil should be excluded for these reasons. Acidic products like citrus should also be limited as they attract flies.

Maintaining a Healthy Worm Bin

• Food scraps should be added sparingly at first. Too many food scraps at once will create a rotting odor if the worms cannot process it fast enough. The temperature can be checked with a soil or compost thermometer after a few weeks, once the worms have adjusted to their new environment. If the temperature is low, more food scraps are needed. If it is high, more bedding is needed; beware that high temperatures will kill worms.

Addressing Problems

• Small adjustments in the ratio of food scraps, bedding and moisture can solve most vermicomposting problems. An excess of dying worms indicates inadequate moisture or too much food. The bin should always be kept moist but not soggy. Ants enter the bin if the mix is too dry, and flies appear when food is left exposed. Fresh food scraps should always be covered with a layer of bedding. A foul odor will be noticeable when the mixture is too wet, causing lack of oxygen that can also drown the worms.