Using red wiggler worms as a composting tool in the classroom is a natural fit. What child--whether attracted to or repulsed by worms--won't find the way these little slippery creatures devour fresh food scraps interesting? Vermicomposting--composting with worms--does not have to be a time-consuming endeavor. Easily create a vermicompost center for a classroom tabletop.
Find two containers that fit together snugly but leave enough room to catch the liquid castings that are highly rich in nutrients and is excellent for fertilizing potted plants.
Drill holes in the bottom of the inner container and in the lid to allow for drainage and air flow, respectively.
Fit containers together and fill the inner container with shredded newsprint to act as "soil," giving your worms a place to stay moist and hide. Wet the newsprint and fluff as needed to keep it from just being a solid mass. Newsprint as it is composted by the worms and nitrogen castings will give your compost an airy texture that is perfect as a soil additive. Regular soil could be used but would be heavy and more difficult to find the worms for any classroom activities.
Add red wiggler worms. Red wigglers are usually sold by the pound at some full-service garden centers, bait shops or online. Bait shops often stock them as "red hybrids" or "manure worms." Red wigglers are small but eat will eat half their weight in a day.
Add food scraps every couple weeks by burying them down a few inches in your newsprint bedding. The best scraps include most veggie and fruit scraps, small crumbs of bread and dry, ground up eggshells. The worms will start digesting food as they start to rot, so it's best to continuously add small bits to allow for a constant food supply.
Harvest your worm castings about every six weeks when the newsprint bedding starts to get dark and soil-like in makeup. The simplest way to do this is to move all your old material to one side of the bin and add new newspaper bedding and food to the other side. After a few days, all of the worms will migrate to where the food is and you'll be able to remove the material from the other side to be used in your gardens.