No, our cats aren’t privileged or anything.

A gentle reader reminds us that it’s been too long since we updated you all on the cat litter compost.

For background, see Installment One and Installment Two

Long story short, cat litter composting can work (under the care of an experienced composter, mind), especially in conjunction with a worm bin–but I’ve found a method I like better.

On the composting experiment:

In our last episode of Cat Box Madness, I discovered my kitty litter wasn’t breaking down very quickly, so I added nitrogen to the mix. That seemed to work well. All except the first 7 inches or so is really nicely broken down all the way through. I still wouldn’t put it as it is anywhere near food crops, even though it is two years old, just to be safe.

To make it extra safe — and useful — I’ve been letting the worms have at it. I’m using it as part of the mix that forms the worm bedding, so cat poo will become worm poo and the garden will be delighted.

That’s how I plan to dispose of all of it, bit by bit. If I didn’t have the worm bin, I’d call it done and spread it under fruit trees or ornamental plantings.

Lessons Learned:

1) Make sure your pile is accessible and easy to turn. Due to lack of yard space, I put my litter in a 50 gallon drum in a narrow, hard-to-access–and hot!–side yard. This meant I never wanted to tend it, and when I forced myself out there, I was pretty unhappy. There wasn’t even enough room to wield a shovel comfortably.

2) A big pile is a good pile. While I made this work in a 50 gallon drum, the best compost comes from a bin which is about 1 cubic meter/yard in size. Smaller bins just don’t heat up sufficiently, and are invariably pokey and hard to work with. If you want to do this, do it big.

3) Careful with the litter you choose. Not many litters make the grade. You can’t use clay litter, or any litter made with deodorants or coloring or “magic crystals” or tiny unicorns. It must be made of 100% plant based material. I approve of both World’s Best and S’wheat Scoop. Pine pellet litter, like Feline Pine, is much less expensive than the clumping brands, and suitably plant based, but under ordinary circumstances, since its not scoopable, you have to dump the whole tray rather often, which leads to a fast build up of material. If you have room for it, this might be okay.  (I’ll have more to say about pine litter further down, though.)

4) You have to add extra nitrogen to your pile to make it work. Even though it’s plenty stinky, the nitrogen present in cat waste can’t balance the heavy carbon loads of the litter by itself.

(Note: You should be an experienced composter before you try composting cat litter, as I’ve warned before, and so you will of course know what I mean by all this talk of carbon and nitrogen–but for those of you who are incorrigible, or simply curious, nitrogen sources you might add to your pile include urine, natural seed meal fertilizers, dried alfalfa, fresh grass clippings and other plant material, fresh chicken, horse, or cow manure, and vegetable trimmings.)

Other than those caveats, cat litter composting works pretty much like regular composting. Keep the pile moist. Keep an eye on it, fix it as necessary. Let it sit for two years at least before you spread it. And then spread it around non-edible plants, or under fruit trees. The fruit trees won’t uptake anything nasty.

It’s totally do-able and I’d do it again. But I’d rather do it again in a larger yard, where I could have a big, accessible compost bin. So now I’m doing something new.

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