How to Make a Worm Bin

Projects seem to get prioritized around here based on necessity–probably the same for most of you.  We have a long list of projects we want to do in our new house, and making a worm bin was not originally close to the top of the list. However, we ran into a problem with the compost…..mainly piles of food scraps…..that made it rise to the top of our list.

Here is a short film my husband Sean (see his website and vimeo page) made about our worm bin; more details on the process are below:

Our compost is a small metal bucket under our kitchen sink, and the idea is that it is filled up and dumped outside in a compost bin.  However, between coffee grounds and veggie scraps it fills up every day, but we weren’t always motivating to take it out every day.  So we’d just throw another round of veggie scraps from making dinner in a bowl, and set it under the sink next to the full compost bucket….and maybe pull something molding out of the fridge and throw that under the sink too.  Then all of a sudden there is a massive pile of rotting veggie waste under the sink….which is so gross.  And on the other end of the issue was where to dump them.  In our old house we had one of those big black plastic, cylindrical composters that set on top of the soil.  The problem was that rats would dig holes in the soil up into the compost.  I’d put rocks on the holes, and they’d dig more holes.  Then the rat population must have grown (BECAUSE WE WERE ESSENTIALLY FEEDING THEM), because some of them moved into our house!  We tried traps….then had to resort to poison when I saw one running down the hall toward the baby’s room.  Fast forward to now, at our new house, loads of veggie scraps, wanting to turn them into something to put into the garden, but wanting a totally contained unit that rats can’t get into.  We only had a wide open compost heap when we moved in, and I didn’t want to dump food there and feed the rats, so I tried digging a hole and covering it, but that filled up quickly.  So I had to just throw the food scraps away.

It just seemed so wasteful to be throwing away scraps that could be turned into fertilizer for the garden, and then later I’d have to go buy fertilizer for the garden.  So I’d be paying to have the garbage company bring my food waste to the landfill, and then I’d be paying to buy fertilizer that I could have been making from that waste.  Thus….the worm bin rose to the top of the list.

My eventual goal on our 5,000 sf lot is to grow most of our own food. Think it can’t be done? People are doing it. Most famously probably the Devrae family in LA; a father and his three grown children who are completely self-sufficient, and even making a small profit, off of their normal-sized city lot.  Here is a 15-minute film about them:

With everything we do, I want to be taking small steps toward sustainability and growing our own food.  For the Devrae family, it is a full-time job for 4 people to keep up with their urban farm.  For us, two working parents and two small kids, we need to take small steps in that direction, and each step needs to save us time and money (rather than consume extra of those).  We need to be realistic that we can’t go all the way to self-reliant overnight, or even in the first year.  But as problems present themselves, and as we have opportunity, we want to come up with solutions that fit into this long-term goal.

Cramming a lot of gardening into a small space must, by its nature, be biointensive.  Meaning, plants need a certain amount of nutrients to grow.  If you have a lot of plats packed close together, the soil will run out of enough nutrients to support them unless you are adding a lot of inputs.  This is where I think I’ve fallen behind on productivity in the past:  not adding enough nutrients to the soil.  A worm bin can help us with this.

Earthworms eat food scraps and yard waste, and their poop is apparently a perfect plant fertilizer.  According to this website, “Worm castings are the richest natural fertilizer known to humans. That’s right: as little as a tablespoon of pure worm castings provides enough organic plant nutrients to feed a 6″ potted plant for more than two months. Worm castings stimulate plant growth more than any other natural product on the market.”  And they would end our compost problem at the same time.

You can buy worm castings even on Amazon, such as these.  You can also buy a ready-made worm composting bin, such as this Worm Factory.  But the concept seemed so simple.  Couldn’t we just build something rather than buying a stack of plastic?

A little searching online turned up a commercial scale red worm farm just an hour from our house!  The Northwest Redworms website has all kinds of helpful links for building worm bins, and facts about the worms.  Apparently, one pound of red worms can consume half a pound of compost each day!  So they would move through our compost and solve our issue pretty quickly, making lots of rich fertilizer in the process.  On this site they also sell Cedar Compost Bins, which looked like something we could make at home, so we decided to try.

From this and other research, I came to realized that the basic concept of the worm bin is this:  a box that critters can’t get into, but that allows air circulation and drainage.  A plastic bin needs holes on the bottom for moisture to drain out of.  A wooden one will absorb the moisture, so doesn’t need drainage holes.  It’s best to have two boxes either side by side, or one on top of the other (like the worm factory), with a screen or other way for worms to migrate between the two.  The idea here is that you fill up one with compost and worms, and over time the worms eat the compost and fill up the box with their castings, and you want to harvest the castings but not remove the worms.  So you start adding compost to the other, empty side, and stop adding any to the full side.  The worms then migrate through the screen or other holes between the two boxes from the side full of castings and not food, to the side with the food.  Once all the worms have moved over, you shovel out the castings, and repeat it all again when the other side fills up.

worms_735px
Worms released into worm bin

With two young kids (4.5 and 1 year old), this project, simple though it may be, proved to be insanely difficult.  I wanted to do this over a few weekends when Sean was working or mostly gone for other obligations, so was alone with two kids, trying to build something in the backyard.  Ha!  Luckily, Sean noticed that one of the small planter boxes in the back yard actually had a wooden bottom as well; it was a box, just with no lid.  All I had to do was put a divider in the middle, and add two lids, and it would be a ready-to-go worm bin.  I then even found that the wooden doors from our old chicken coop (which had been beautifully build by some architecture students, so we’d moved it here to possibly use as a shed, but then decided not to…) fit perfectly on each side of this planter.  All I had to do was put the divider in the middle and attach the two doors to the top.  Even this took me two full days of trying!  Eliza just started walking, and the minute I set her down in the grass she’d want to walk straight into all the dog poop.  So then I had to start by scooping all the poop.  Then I’d try to start, and she’d want to roll around in the area where the poop had been, so I’d move her, then she thought it was a game with me moving her and her running back over there.  Then I got her distracted by digging in one of the other raised beds, but no sooner would I lift the drill than she’d have a handful of dirt headed for her mouth, and I’d need to drop everything and run over.  Then everyone was tired and hungry, and we’d need to go inside for snacks and naps.  Etc., etc., etc.  This simple project moved so painfully slow.  But it did get done!

Raised bed turned into worm bin with divider in middle and doors on top
old chicken coop the doors came off of


Since the Northwest Redworms site was only an hour away, we decided to make it a field trip and drive out there with the kids to get the worms.  Thought it would be a fun learning experience.  It turned out to be very interesting….As one may expect of someone who is making his life work worms, the owner was quite eccentric.  The “farm” was a series of old sheds with piles of scrap materials all around, and chickens and geese running around.  He carefully weighed out a pound of red worms, then led us to the “cat condo” where he could run our card.  He also has a cat boarding business in a trailer (the cat condo), and in the middle of that trailer is his desk.  We visited with the cats while he ran my card.  When I got back to the car, I realized he charged me more than advertised on his website….but since we never discussed it I don’t know if there was a valid reason or not….We took our over-priced worms home, through an hour long drive in the rain and the dark with cranky kids.  The field trip wasn’t quite what I envisioned….but what ever is!

We returned home to put a few shovels full of finished compost (as recommended by the worm guy) in the new worm home, then layers of ripped up paper bags (for worm bedding), then fresh veggie scraps on top of that.  I dug down to the finished compost layer, dumped in our new worms, then arranged the other stuff around them.  Digging down to check on them a week later, and I found tons of worms all over in the bin, so they made it!  It will be interesting to see how long it takes to fill up one side with vermicompost.  Will update the blog on this project later!

(Side note:  it is always a difficult balance between including the kids so they learn, and getting the job done.  In this case, I did let Cedar help use the drill to put some of the screws in the hinges, he was part of purchasing the worms and putting them in the bin.  And as you saw in the video we made, he did learn!  He was able, unprompted, to explain the entire worm bin system.  And he’s four and a half.  But how much longer did it take me to get this task done by including the kids?  Much, much longer.)

howtomakewormbin

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