Worm composting is an enjoyable way for kids to learn about gardening and the basics of composting, while making the world a better place by keeping trash out of landfills at the same time. Being aware of the basic facts surrounding worm composting can make it a safe, educational experience --- for the kids, the worms and you.
Worm composting is a kid-friendly composting method that involves just a few simple materials, including red worms, a worm bin, worm bedding and kitchen scraps. Your worm bin can be metal, plastic or wooden; for children, plastic cleans up easily and doesn't have any sharp edges that may cut little hands. Easy-to-obtain worm bedding materials include shredded newspaper and cardboard, as well as leaves. Fruit and vegetable waste are probably the easiest kitchen waste for children to use with worm composting; other acceptable options include tea bags and coffee grounds.
The size of the worm bin is an important consideration when worm composting with kids. As a general rule, allow 1 square foot of surface area per lb. of weekly food waste you plan to provide for the worms. Your containers should also be no taller than about 12 inches tall. Rather than using a single large bin for your worm composting, think about using several smaller, more portable worm bins, especially if you're working with a group of kids, such as in a classroom. This allows the children to play a more active role in caring for the worms.
When you're worm composting with kids, plan to allow about three months for the project from start to finish. This time frame allows children to experience an entire cycle of worm composting. Once you set the bin up, the children simply have to maintain the bin (with your supervision) by adding food for the worms -- usually on a daily basis -- and making sure the bedding stays moist. According to Canada's Office of Urban Agriculture, the worms should produce enough finished compost for you and the children to harvest within about 10 weeks.
When kids are composting with worms, it's important that they understand the process that's going on. Not only do the worms consume the food, but once you place it in the worm bin, millions of microscopic bacteria help break the matter down to facilitate decomposition. The worms produce castings (manure), which together with the soiled bedding makes a rich fertilizer you can use to increase the nutrients in garden soil. Children who understand this process gain a new appreciation for worms and also have a clearer idea of the important role composting can play in maintaining healthy soil and a healthy world.
Make sure kids understand that worms can only consume certain kinds of kitchen waste. According to the Wisconsin Department of Natural Resources, avoid dairy products, meat and bones, and dog or cat feces. Never let children add any materials that aren't biodegradable, such as rubber bands. Although children can do a lot of the work that goes with worm composting, an adult must be available for supervision and guidance at all times.