At select workshops, residents can purchase backyard and worm composting bins at a discount. Cash or check only. Limit of 2 bins (of each kind) per household. Supplies subject to availability. If supplies run out, other purchasing arrangements will be made. The composting worms provided with the worm bins are African Red Worms (Eisenia fetida). These worms are commonly called Red Wigglers, and are the most common type of composting worm. They can process large amounts of organic matter (up to half their body weight per day). They also reproduce rapidly and are very tolerant of variations in soil conditions. Nature's soil aerators, worms will improve and condition the soil as they burrow in search of food. Composting worms excrete a very valuable natural fertilizer (called castings), which contain 5x the nitrogen, 7x the phosphorus, 3x the exchangeable magnesium, 11x the potash, and 1.5x the calcium as are normally found in 6 inches of top soil. Other names for Red wigglers include Tiger worms, Garlic worms, Manure worms, and Brandling worms.