Composting With Critters: Worms, Larvae and Friends
May 3, 2017
A compost pile teems with microscopic life, literally millions of bacteria that are digesting and decomposing organic wastes into the wonderful soil amendment called compost. But there are larger life forms in a compost pile, too: earthworms, millipedes, sowbugs, springtails, beetles and insect larvae of all kinds. Some home composters have harnessed the power of two of these critters – worms and larvae – as the primary means of composting organic wastes.
Using worms for composting, called “vermicomposting,” is a long-established method. Worm compost bins can be kept indoors year-round, or outdoors at suitable temperatures. Worms create compost by digesting organic materials, which are passed through the worm’s body and released as worm castings. The worms organic wastes quickly into rich worm castings for compost.
Red wiggler worms are the preferred worms for composting; they are available from garden centers and compost supply providers. Red wiggler worms are especially good at digesting higher-carbon wastes, like leaves and paper, breaking those down into beneficial castings for compost. Keeping a healthy worm bin does not require extensive effort, as long as some simple guidelines are followed. That includes providing the worms the proper mix of food and moist bedding.
Intentionally composting yard and kitchen wastes with larvae is a more recent technique. The larvae used
are black soldier fly larvae, creatures that have long been found in decaying manure and outdoor compost piles. Black soldier flies (Hermetia illucens) are larger than common flies, approaching an inch in size. These flies live only a few days after laying eggs, which then hatch and grow into larvae. Black soldier fly larvae are flat and gray with a tapered head and have been used to digest agricultural, foodservice and municipal wastes.
Black soldier fly larvae are scavengers. They have very powerful chewing mouthparts that literally tear up organic wastes, according to Texas A&M University. One benefit of using black soldier fly larvae to compost waste is that they may chew up the waste before it starts to decompose. This helps immediately eliminate odors associated with decaying organic matter.
Black soldier fly larvae are often found in and around worm compost bins, especially outdoor worm compost bins. This can be good for composting, because the two prefer different types of organic matter; but larvae that are not managed can also outcompete the worms and take over the bin, according to information published by Oregon State University. Screens or other barriers on the worm bin can help manage this problem by keeping flies away.
Plans to build your own worm bin are widely available. There are also lots of DIY recommendations for using larvae in composting and how to encourage black soldier fly populations. Larvae have been used in the South to digest large amounts of manure from farms, and universities in both New England and the Pacific Northwest have led the charge to put larvae to work in digesting municipal wastes.
Like any other composting project, there’s both science and some art to designing the best way to use worm or larvae to make your compost. If you decide to try harnessing red worms or black soldier fly larvae to digest organic wastes, follow guidelines from reputable sources and seek advice from experienced composters. Then give yourself room in your setting for experimenting with how these amazing composting critters can help you recycle and return lawn and kitchen wastes into the wonderful soil amendment called compost.