Bin there, dung that

finished bin-800When it comes to compost, we don’t really know crap.

There are a million schools of thought on the best way to turn those leftover bits of food — the vegetable stems, the eggshells (oh, how many eggshells), the untenable march of giant leaves from the neighbor’s sycamore tree — into fertilizer. Three-station bins are popular, with a chamber for new matter, a chamber for active turning and drying, and a chamber ready to use as soil amendment. But we didn’t have enough space on the wee homestead to warrant such a sacrifice of real estate.

At least that’s what we thought.

So a few years ago, we opted for a stand-alone compost bin on a spit, where we could just dump in our new scraps, give it a spin every week or two, maybe give it some water now and again, and let it cook up into dark, loamy, nutrient-rich clods. The one we found was a repurposed olive brining barrel, which came shipped unwrapped, with the cedar leg-frames tucked neatly inside the barrel.

This system had some obvious benefits:

  • The space savings I’ve already talked about. We stood this up in otherwise unusable space under our deck stairs, and it’s all we needed.
  • It looks more than a little bit like an R2 unit from a long time ago, in a galaxy far, far away.

But we discovered one pretty big disadvantage, and this year it finally got the better of us. That is, there has to be a pretty long dormant period, where you’re not adding any new material so that the microscopic critters can digest and transform the organic matter into more or less a final state. (Not all of the critters are microscopic. Fruit flies are all over the inside of that thing, and so are some pretty impressive, largish white worms that, I’m pretty sure, are just waiting for a mothership to take them to an asteroid belt, where they can find a larger crater for a long-term home.)

That dormant period wasn’t an issue for us back before we had a winter farmers market. We would just use the winter, when we were eating less fresh food and more preserved stuff, for the “dark time.” Of late, we’re eating fresh almost all year, and now we’re throwing away a lot of veg scraps. It’s not the end of the world, but seems, literally, wasteful.

The good news is, after planting a fig tree by the fence in the side yard last year, then building a trellis beside that for our blackberries, then tucking a firewood storage rack next to that this winter, we still had about 7 feet of real estate left along the fence-line. This is right there in full sun on the southern side of the house, too, making it perfect for a little, ahem, compost office.

Besides, y’all know I don’t need much of an excuse to break out the chop-saw.

lumber for compost bin -- and Seamus

Let’s do this!

So I did a little Googling, found a three-stage compost system with a design I liked, converted it to two stages, compressed the dimensions a bit, and started cutting lumber.

Why just two stages instead of three? Because the barrel will still be our first stage. It’s dog proof (sorry Seamus), it’s easy to spin without going “Exorcist” on your clothes, and it’s covered to keep odors in.

We’ll put our food scraps and yard refuse in there until it gets unwieldy. Then we’ll move it via wheelbarrow to the first chamber of the new compost bin. From there we can keep fueling it with leaves and keep turning it with a shovel or pitchfork until it’s ready to use. Theoretically, by the time we use all the fertilizer from one chamber, the other one will be ready to go.

The construction of the unit is pretty straightforward, with a minimal 2×4 side frame, 1×4 cedar planks to buttress the sides and backs, chicken wire to hold the compost in place on three sides, and 1×8 cedar panels on the front that can be easily slid up and out of the way for access to the piles. There’s no floor required.

My very scientific plans are here:

plan sketch-800

You can get a pretty good idea of the framing from this shot of the nearly finished bin:

assembled frame-800

Now, a couple of disclaimers for those who haven’t done much composting:

  • For a quick compost like this, you shouldn’t add meat, dairy or oils to the organic matter. All of that composts at a much slower rate and won’t be finished when the rest of the stuff is. Egg shells are OK, thank the stars.
  • Pet poo is also a no-no.
  • Shrimp shells are OK. In fact, they’re a great source of nitrogen, but need to be processed a bit to minimize odor and exacerbate decomposition. Learn more about that here. (Full confession, we usually just throw ’em away, though we’re toying with adding them to the mix now.)

Other resources

  • A good primer on composting.
  • A standing compost barrel, like ours. There are lots of variations on this — some with the horizontal barrels, and others with thin, metal-frame legs. I don’t know about the horizontal barrels. They’re probably fine but take up more space. I would stay away from the metal frame legs, based on the weight that our barrel regularly carries.
  • The Rodale’s Organic Life plan for a three-chamber bin which was the basis for my design.
barrow and bin-800

World’s coolest, most decked-out wheelbarrow moves the first load of compost into the new bin.

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