How to Make a Cheap and Portable Worm Compost Bin
My interest in worms began at an early age when I realized the creatures had special powers; they could make my sister squeal and lure lake fish to my awaiting hook. The night before our fishing safaris, we would water my grandparents’ lawn, and with the finesse of a jewel thief and speed of a mongoose, pluck up night crawlers escaping from their soggy dens. (Don’t be fooled, the slimy critters are fast.)
Nowadays I appreciate them even more as natural alchemists, turning green garbage into gardening gold. A little red wriggler can breakdown a substantial amount of kitchen scraps– an estimated one quarter to one half pound of waste every day for every pound of worm.
I came up a large capacity do-it-yourself worm bin as a cheap and easy way to enjoy the benefits of vermiculture without a lot of building fuss and preparation. The first worm bin examples are smaller versions from my composting past.
The Green Cone food composter is an great urban solution for food wastes. A hole is dug, the basket dropped in and the top cone and lid attached. Vegetarian food scraps are added daily, and some time later, worm castings and compost can be removed and added to the garden. This system works best with two cones. When cone 1 is full, start supplying cone 2 with edibles. By the time cone 2 is full, cone 1’s contents will be ready for use as a soil amendment or light fertilizer. City of Seattle residents can buy the $100 bin for the subsidized price of $25 or two for $40. It’s a rotting good deal. Learn more.
The Cadillac of Worm Composters is a five-layer tower version that’s a little more complicated and requires closer operational attention. It’s a pricey little bugger at $100, featuring a drain spigot for the removal of excess moisture. I use the coffee-colored liquid as a fertilizing compost tea. Unfortunately this plastic stackable unit couldn’t keep up with my volume of leaves, rinds, peels and stalks.
Tah dah! Being cheap is the mother of my invention. Here’s the solution, an $11.99, 33-gallon plastic waste can on wheels with a locking lid. A few added holes, bedding, and worms, and you’re good to go.
Begin by drilling drain holes on the bottom of the can, which allows liquids to escape. (We’re not trying to create primordial soup here.) At the other end, drill quarter-inch holes in the lid (on both sides) to allow for air circulation and venting. Worms need oxygen, too.
Lid off, line the can with shredded newspaper, then toss in ten inches of peat moss (fine compost and coconut coir work, also). Mix shredded paper into the top four inches and then add your red wriggler worms to the mix with a splash of water. Top the whole thing with your veggie leftovers–old lettuce leaves, apple peels or asparagus ends, etc. (My worms eat well.) Add the lid and lock it in place.
Every other time you add plant scraps, toss in some shredded paper for good measure and bedding material.
Tips and things to consider for your Worm Bin Wonder
- The bin needs full shade and to be kept cool
- Get starter worms from friends who already have worm bins
- Coffee grounds can be added to the mix
- Red wrigglers can be purchased at nursery, garden centers or online
- Red wrigglers compost food more quickly than regular earthworms
- Don’t add animal products (though crushed egg shells seem okay)
- Add a layer of shredded paper at least once a week
- Make sure the contents don’t dry out (unlikely in most cases)
- A two bin system works well. When one is full, move to the other and alternate harvesting compost.
- Screen finished compost, return worms to bin and begin process again.
- Spread the compost love around the base of your favorite plants
UPDATE: Your Worm Bin in Winter
Option 1: Store in non-freezing out building
- Roll the can into a garage or storage shed where temperatures remain above freezing
- Because the can drains, slip a large plastic yard bag over the can about one foot up the side and tape to can.
- Remove bag and drain liquid as it accumulates
- Or place over drain hole
Option 2: Insulate outdoors
- Dig a hole in a garden compost pile
- Set the worm bin inside
- Cover to top rim with leaves or compost
- Cover lid with a couple layers of burlap
- I use green coffee bean bags (The Roasterie is just down the road from me.)
- Decomposition creates warmth and the insulation helps retain it
- City of Seattle: food waste composting
- Washington State University: Everything you ever wanted to know about worm composting
- All about the earthworm and its physiology