School:Worm: Worm Bins


	recycling at school
	teacher's resources
	worm composting
		worm workshops
		worm bins
		the worms
		feeding the worms
		maintaining the bin
		harvesting the vermicompost
	links for kids!
	School Newsletters

worm bins

Worm bins can vary in size and material type. Bin sizes can range from small shoebox-sized bins up to large 4 ft by 8 ft by 2 ft worm "estates." Obviously, the larger the bin, the more worms it will house and the more food waste they will consume. While several schools vermicompost nearly all of the food waste generated at the school and have a set of 4 ft by 8 ft bins, by far the most common type of classroom bin is a converted plastic storage box of approximately 18 gallons in capacity

What to Use as a Bin?
The main attributes of a good bin are that it keeps the light out, has a snug-fitting lid (for classroom bins), provides for ventilation and drainage, and is big enough to handle the desired amount of food waste. The 18-gallon bins can be started with 1,000 worms (1 pound) that, once acclimated, will process one half to one pound of food waste a day.

Converting a storage box is relatively easy and requires only creating small holes in the box. There are also several vendors throughout the nation that sell deluxe ready-to-use plastic bins.

Where to put the bin
Worms should ideally be kept in an environment that is 55-77 degrees Fahrenheit. Because of this, indoor locations are usually preferable for classroom or home bins.

The larger bins, however, can be kept outside because the thicker wood bin and larger mass of the vermicompost insulates the worms and protects them from relatively extreme temperatures. In most areas of California, a shady location will probably be best.

In areas with very extreme climates, extra insulation (usually hard foam core) may be needed to keep the worms active in outdoor bins. (Note: Worms will live at temperatures both above and below the 55-77 range. In general, the larger the bin the greater the temperature flexibility).

Bedding

Once the bin is made, bedding must be added. The bedding provides a moist home for the worms, provides the proper carbon/nitrogen balance, and covers the food waste to minimize odors. The layer of bedding should be at least 6 inches deep after moistening. The bedding will be consumed along with the food waste to become vermicompost.

Shredded paper is the most common worm bedding because it is readily available to most vermicomposters. While newspaper is usually used at homes, the white paper found in schools, offices, and institutions also makes an excellent bedding material. Glossy advertisements and magazines should be avoided. To turn paper into bedding, simply tear the paper into long one-inch-wide strips. If it is difficult to tear, try tearing in the other direction and it should be easier.Other common bedding materials include composted manure (not too fresh or hot) and shredded corrugated cardboard.

As a general rule, fill the bin with dry bedding material and then dampen it to a point where it is thoroughly wet but not dripping wet. "As damp as a wrung-out sponge" is commonly used to describe the proper moisture level of the bedding. The worms can be harmed if the bedding is too dry or too wet. A three-to-one ratio (by weight) of water to bedding is a general guideline. A pint of water weighs approximately one pound.