“Behold this compost! behold it well!”–Walt Whitman, “This Compost”
For fourteen years, I have housed another species in my home, this one at least deliberately. Eisenia fetida, a species of earth worms, are commonly known as red worms or red wigglers. They are less adventurous than the ones you might find a few inches below the surface of the soil around your yard. I like to joke that these are the “couch potatoes” of earth worms: they can eat half of their weight in a day and they generally don’t move around a lot. If you think about it, they are the perfect house guests, especially because they will eat rotten leftovers. These earth worms also make great pets: you don’t have to take them on walks, they won’t disturb the neighbors, and you don’t have to get a worm sitter when you take a trip.
Hosting these worms is more than just an inter-species “living together” experiment. It is part of my attempt at being more self-sufficient and finding a way that my actions can overlap easily with my beliefs. But before you think I am going to get up on my soap box, err worm bin, I will not. I like science and pets and gardening and the worms help to indulge all those fancies. Over time it has become a hobby and part of my practice, a simple way to unite with my discards. And I could talk about compost until the worms come home. Occasionally, I give how-to-compost workshops and I like to point out the ease of effort. Unlike many other endeavors, it requires no collaboration, no infrastructure, and no one even needs to know.
These red wigglers are the worms for indoor home composting. Lots of people can try backyard composting, but if you are without a yard or an outdoor space, what to do? Vermicomposting, or worm composting is the answer. It’s also a way to compost without worrying about winter weather, without worrying about the next door neighbors, without worrying about wildlife that might be digging in a backyard bin. Thanks to Mary Appelhof, known as the Worm Woman, who wrote the now classic Worms Eat My Garbage in 1982, it can be a fairly simple and painless and–believe it or not–an odorless process.
First think about what all living things need: air, space, food, water, and proper temperature. Let’s see how these apply to our friends, the red worms.
Meet the Worms
When I talk about the worms, most people think I dig them up from the ground or buy them at a bait shop. Yes, they are a type of earth worm like you find in most soils, but the ones most of us find in North America are deep dwellers, sometimes traveling more than a foot beneath the topsoil. Those earth worms are big soil stirrers, mixing up the organic (leaves, humus, decaying plants, decaying animals) with the inorganic (sand, clay, rocks) parts of the soil. Eisenia fetida, the red wigglers, look small and red, are shallow soil dwellers that consume large amounts of decaying matter and do not move around that much. That they eat a lot and stay put are just what you want from worms that will become your new roommates. They are a bit small for fishing worms, but they can be bait for fishing if you double (or triple) them up on your hook. If you bring home night crawlers, worms that fishers love, they’ll do just that. They’ll crawl right out of the bin and probably won’t eat much of your peels and cores and crumbs. Contact your local bait shop or gardening store, but make sure to request the worms by Latin name as many species share common names. If you order them, check out Flowerfield Enterprises, the group Mary Appelhof started, that continues her amazing work with compost research and education.
Air We Are: Worms Breathe
Worms need oxygen and earth worms breathe through their skin. That’s why we see them up on the sidewalks after a spring rain. They’re drowning in all that water. Before you fill up the bin with worms and bedding, drill some holes in the sides of the bin and in the lid. For a small bin, 10 or 20 holes spread around the lid, and a few holes on all four sides will be sufficient. This isn’t an exact science and if you keep the lid on loosely, that will make up for any holes you didn’t add. Make the holes no bigger than 1/8 inch (0.32 cm); you don’t want to make an escape hatch for the worms. (We’re not talking wormholes and shortcuts into the space-time continuum. That will have to save for another day and another post.) Back to the bins, some folks will advocate for holes on the bottom for drainage, but then you can only place the bin on certain floors or surfaces. Moisture and water will be addressed below.
A Space of Their Own: a Bin and Bedding
The idea is to provide a healthy welcoming environment for your worms and then they won’t need to explore your home. Start with a pound or so of worms, that’s as many as a thousand worms, and give them some space. I suggest a small box, whether plastic or wooden, like a small plastic storage container. I’ve had wonderful wooden bins, but I like the portability of a plastic box, especially because my worms go on tour for workshops and events. In fact, you might have a storage box taking up space under the bed or in a closet that you can use. These lovely little worms are like suburban sprawlers, so the more surface area the better. While an old five-gallon bucket seems like a good idea, you won’t be able to house many worms. These worms prefer to live in the top few inches of the soil in their native habitat, so no deep boxes or bins.
Now you need some bedding. Bedding is anything like ripped up newspapers (newspaper works best as it absorbs moisture more effectively than other types of paper) or old potting soil or leaves, or a combination. You’ll need at least three or four inches of bedding, so the worms have space to move in and amidst the layers. You will constantly need more bedding as you add food, since you will always bury the food under a layer of leaves or ripped up newspapers. The bedding helps to absorb moisture, thus cutting down on smells. Burying food under the bedding also helps to prevent fruit flies from finding your compost bin and making it a home-base for breeding. If you recall biology experiments, fruit flies can reproduce faster than you can say “leftovers.” Luckily for us, they can’t burrow, so burying your food scraps will help to keep the fruit flies out of your worm haven. Throw in a small handful of sand, the grit will aid the worms’ gizzards in breaking down their food. Adding a scoop of healthy soil will help to introduce microbes into your worm bin. Now that you have your bin, find a convenient place to store it. I have kept mine in the middle of the living room floor (post college apartment, no furniture), under the sink in the kitchen (convenient for adding food scraps to the worm bin), and in the bottom of the coat closet (out of the way, but close enough to the kitchen, and no my coats don’t stink).
Food From the Heavens: Leftovers and Rotten Bits
You feed the lovely little creatures food scraps and discards. Banana peels, coffee grounds, apple cores, tea leaves, rotting cabbage, anything that would be considered fruits and vegetables or plant waste, including clippings from potted plants. Grains, pastas, and bread are fine as well. As long as it doesn’t contain meat or cheese, it is fit for the worms. You’ll need no more than a half pound or so of food a day, preferably food that would have gone into the garbage. If you measure your food waste, you’ll be surprised at how quickly a half a pound food adds up to a lot. A healthy pound of worms can eat half their weight in a day, which is about three and a half pounds of food a week. Cut it up into small pieces, like you might Hors d’oeuvres for a cocktail party, but these are the dregs, the leftovers, the rotten stuff. Bury the small food bits under a layer of bedding and have more bedding ready as you feed. After that, you leave the worms alone. I feed them a couple of times a week, or as I have food to give, when I am cooking and have peels and stalks to share. All the experts say not too much of any one food, but relax. I have found that as long as you watch how much you place in the bin, spreading the food around evenly in the top layer and then burying it under layers of bedding, your worms should be fine. In addition to food scraps, small bits of paper like tissues, paper napkins, coffee filters, and tea bags can all be consumed by those little worms. These used, soiled papers will become part of the bedding.
It’s estimated that 40% of all food is thrown away in the U.S. While the worms can’t help us to solve that entire problem, as we feed them they can help make us more aware of what is being wasted. We can also keep small amounts out of the landfill and turn them into something better: compost.
Water, Water, Water
Worms need water, but usually you won’t need to water the worm bin. There’s quite a bit of moisture in our food scraps. If you reach into the bin and grab a handful of castings (the black soil) and squeeze, you may get a few droplets. It should feel damp,like a wrung out dish rag. If you see standing pools or puddles in the corners of the bin, it’s too wet and the worms will begin to crawl out. As you can imagine, this would not be an ideal situation. Luckily, it’s easily preventable. Keeping the lid off for short periods of time can help to dry out the bin. Adding more bedding will also help to absorb the moisture. If you still seem to have lots of moisture, pour out the excess. An old turkey baster can be used to suction some of the water out of the bin. You can give this water (or compost tea) to house plants or your plants outside.
Worms Need Warmth
The red wigglers are a tropical species, native to Asia. They prefer warm (or worm) climates, around 55-77°F (12.8-25.0°C), which is within the temperature range of many human homes. My place gets a bit hotter than that in the summer and still they live and eat and breed. They can survive outside of that temperature range, but they will slow down in their consumption of your unwanted leftovers. Keeping it close to that range is best for the productivity of your worm visitors. For those who would relegate their worms to a basement or garage, check the temperature of those rooms as they can vary widely by season.
Inside vs. Outside
Composting with worms is similar to composting in your backyard. Because lots of soils have worms, people confuse these separate methods of composting. Composting with Eisenia fetida (red wigglers)–I’m rattling off the Latin name again, so that you bring the right worms home–is mainly an indoors endeavor. If you’re squeamish about the idea of worms in your home, this may not be the activity for you, but maybe it is, if you have read this far.
For those concerned about the possibility of inviting an exotic, invasive species into the garden, if these worms make it outside into your yard, they will die in the heat or the cold and won’t spread. That said, there is no need to invite these worms into a backyard compost pile. If you have worms in your yard, they will find your backyard pile. Even if you don’t have earth worms in your soil outside, backyard composting can occur with all the other microbes and decomposers that do live in the soil.
Using the Black Gold
Once the worms begin to eat your food scraps, you have to go back to the basics. What goes in, comes out. Like most beings, once we eat, we excrete. Well, so do the worms. However, their excrement can be called castings, or gardener’s gold, or manure, or worm manure. Whatever you call it, it’s the deep black part of soil full of nutrients that plants need. Food waste becomes the food of those decomposers which eventually becomes the food of the soil, the food required by plants in which to grow. It all comes ’round. The castings will look like the beautiful dark part of the soil. It’s still amazing to see tea bags, orange peels, coffee grounds, and ripped up newspaper transform into the humus. In about three to four months you will have wonderful worm castings. Mix three parts potting soil with one part castings and you have a nutrient-rich plant mix. You can also use the harvested castings as a top-dressing for your potted plants that need some nutrients and extra love.
Harvest the castings by scooping out trowels full as you need. Or use the quick and dirty method: dump the contents of your worm bin onto a tarp and slowly separate the worms from the castings. The worms will go down into the bottom to avoid the light and you can grab what you need before the returning the unfinished compost, worms, and bedding to the bin. And it begins again. . . Have fun and learn about the worms as you go.
Oh, and a sense of humor is helpful with most worthwhile endeavors. Worms lend themselves to all types of jokes. I refrained from lots of my worm puns and compost humor, but I will leave you with one joke. What did the quiet worm say to the joking worm?
You have a great sense of humus.