Indoor Composting: Making a Worm Bin

Yikes! There are worms in my kitchen! Sounds gross, right? Well, no, not really. You would never know I keep composting worms unless you look under my kitchen sink. There in a closed bin (with no odor, mind you), are squiggly red wigglers, quietly and happily dining on my garbage, making lovely “black gold”, nutrient-dense compost for the garden.

Vermicomposting can work well indoors

Compost is great for the garden because it contains nutrients like boron, manganese, iron, copper, and zinc that plants need to grow. And since I throw away so many vegetable scraps, it seemed like a waste for them to end up just rotting in a landfill. I had been thinking about composting for a while, and was trying to figure out a way to do it that would work for my small space. My postage-stamp size courtyard was way too small for outdoor composting, so I looked into other methods.

I found a good book, Composting Inside & Out, which talks about the benefits and rewards of composting, then walks you through all the different methods. I settled on vermicomposting because it seemed manageable, economical, and held great reward. That reward, worm castings, also known as worm poop, are the finished product, extremely high in nutrients needed by soil and plant life. Castings can go directly into the garden or made into a liquid “worm tea”.

This author of this book calls herself "The Urban Worm Girl"

All you need to start a worm bin is a 14-gallon plastic storage container with a tight-fitting lid (approx. $7), a drill, a few inches of soil, 1 pound of red wigglers, fruit and vegetable scraps, bedding material such as leaves, newspaper, paper or cardboard.

First, I drilled about twenty 1/4″ holes around the top sides of the bin, bottom, and lid. Then I added about 4 inches of organic soil.

A 14-gallon plastic storage bin with holes drilled into the sides, bottom, and lid

I got the worms from a local kid, a very enterprising 12-year-old boy who earns money selling red wigglers. These are not your common earthworm. They are Eisenia Fetida, and should never be released into the wild.

My cat, Oliver, says hello to the worms

I added the worms to the bin. They don’t like light, so they quickly disappeared into the soil.

The red wigglers are introduced into their new home

A red wiggler up close. I named this one Squirmy.

After adding the worms, moist bedding goes on top. Suitable bedding includes shredded newspaper or copy paper, torn cardboard or egg cartons, leaves, paper towels, dryer lint (no dryer sheet). It’s important that the bedding is moist. It should be as moist as a wrung-out sponge, not dripping wet. I added dried leaves to my bin and sprayed them down with a water bottle.

Suitable bedding material

Finally, food. What do worms eat? They like a vegetarian diet, mostly fruit and vegetable scraps like apple cores, carrot peels, bananas, lettuce, broccoli. But in limited amounts, they also like coffee grounds, breads, crushed egg shells, tea bags (remove the staple). Do not feed worms meat, butter, dairy, garlic, glossy paper, leeks, hot peppers, onions, oils, spicy foods, green grass or too much citrus. If you have a large rind, like cantaloupe or pineapple, you will want to chop it into small pieces first.

Fine dining for my new wormy friends

It’s important to bury the food scraps! This keeps away fruit flies. If you notice fruit flies, you’re not burying the food scraps deeply enough. But you can also freeze the fruit peels first before adding them to the bin to really help keep those fruit flies away. This is a good idea in the warm weather months. You shouldn’t notice an odor with your bin, but if you do, you may be feeding the worms more than they can eat. Back off a bit and see if that doesn’t solve the problem.

I’ll do a later post and let you know how things are going with the worms, how to harvest the compost, and make worm tea. In the meantime, I found this resource helpful: urbanwormgirl.com. Also, another good book on vermicomposting is Worms Eat My Garbage.