It’s been almost a year since I last talked about our “pet” composting worms, so I thought I’d revisit the subject and share some information on how we actually built our worm composting bin. January is a great time of year to start worm composting because it’s cold enough in much of the Northern hemisphere that an outdoor compost pile is frozen over, killing the microbes and halting the decomposition process. In addition, it’s usually so cold that you want to avoid going outside unless absolutely necessary. Worm composting solves both of these problems because when kept inside, worms can break down vegetable or fruit food scraps all year round.
For a while, the future of our worms was deeply in question. A few months ago, Chris was ready to throw the worms out into the garden, even though he had initially advocated adopting them. (This is an ill-advised thing to do. Depending on the type, they’ll die because they’re not suited for gardens or they’ll process too much organic matter and be a bit of an ecological menace.) This frustration came from a two-fold issue. The first problem manifested in the spring, when I tried to get the compost (worm poop) out of the bin for gardening. As we have a two box system, I transferred all of the worms out of one box and into another. Apparently, they were very disturbed by this move, as many attempted to escape and ended up dead and stuck to the basement floor. Very sad. The second issue was an increasing fruit fly problem. Every time we gave the worms a bit too much food, fruit flies laid their eggs and we ended up loads of nasty flies that are incredibly difficult to get rid of. Thankfully, once the worms calmed down and we solved the fly problem (more on that in the next entry), the worm population rebounded. This fall, when I used worm castings in my lasagna gardening preparation, I removed the compost by hand/shovel instead of trying to move the worms themselves, which seemed much less traumatic. Currently, the worms are doing very well and plowing through their food.
If raising worms sounds like a fun home sustainability project, it’s actually quite easy to set up a system. Although you can buy a worm composting bin for $50-100 online, you can make one yourself in an hour with no more than $20-30 worth of materials. (And if you’re clever about recycling, possibly for free.)
Building a Worm Composting Bin
– 2 stackable, large, shallow plastic bins with lids, recycled/reused if possible; dark-colored is best
– Electric drill
– Wooden or other rods (only if necessary; described below)
– Dark paper or duct tape to darken the bin if it is transparent
– A small amount of dirt
– Organic materials
– Red wiggler worms – You can get some from a friend who also worm composts or buy approximately one pound. I bought them from Compost Critter. Other species also work, but these are the most common. However, normal garden earthworms will not work. I recommend purchasing the worms after constructing the bin, as they cannot stay in their packaging long after they reach you.
1) Drill 5-10 large (¼ inch) holes in the bottom and sides of one of the plastic bins. The number of holes will depend on the floor area of the bin. They should be large enough to allow water drainage.
2) If the bins are translucent, cover the lid of one of the bins with dark paper or fabric. You can use duct tape, as we did, but it holds in a lot of moisture, especially if you are putting in mostly wet foods. I would recommend using paper or fabric instead.
3) Drill holes in the lid you covered with dark material. These don’t need to be very large, as they are for air.
4) Stack the bin with holes in it on top of the bin without holes in it. The bin on the top will be where the worms will live and the bin on the bottom will catch any water that drains. Honestly, ours doesn’t have much drainage, but it’s good to have the ability to drain if necessary.
5) If the bins are stacked tightly, you may need to separate them a bit to maximize air flow. We stuck thin wooden rods in-between the bins to do this originally. Our rods rotted a bit, so we took them out. It seems like the rods pressed against the plastic enough that they don’t stack nearly as tightly as they used to.
6) Add a very small amount of dirt and a layer of crumpled newspaper to the bottom of the top bin.
7) Add the worms. Wait a few days for them to get accustomed to their new home before adding food. It’s likely they will try to escape, and you may end up with a few dead worms around the box. You can discourage this by leaving the light on wherever the worm box is.
8) Once a few days have passed, add organic food scraps. The worms seem to like soft food the best, and avoid harder objects like broccoli stems or papery ones like onion skins. Don’t add too much food at one time or it will attract flies. Add a layer of newspaper over the food to prevent fruit flies and provide them with more bedding.
9) When the worms have produced enough compost to be useful, harvest the compost. You can also make a multi-bin system, where in theory, the worms should come up to the second level if you place food up there, allowing you to harvest compost from the first bin. However, very few of the worms did that in ours and I’ve found it less traumatic for everyone just to harvest the compost by hand.