A gentle reader reminds us that it’s been too long since we updated you all on the cat litter compost.
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.
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.
The New Paradigm
The way it works is that pine litter, when it meets moisture, expands and crumbles into sawdust. This dust just builds up in a regular box, but in these perforated boxes the dust falls through to the bottom bin. You help it along by giving the box a shake when you’re scooping. This construction isolates the pee-soaked dust from the poo–and the clean, intact pine pellets. Once you scoop the poo out you’re left with clean, whole pellets.
The following photos will probably explain this better:
You could of course DIY this system. See some notes at the end for tips on that. I considered it, but for various reasons decided to throw money at the problem instead of making it a project.
I really like this system because
a) It’s much neater. Pine litter is less dusty than clumping litter, which means less tracking, less dust on surfaces, cleaner cats.
b) And it’s cheaper. Pine litter cost less than clumping brands, and I’ve heard that Equine Pine, bought in bulk, is much, much cheaper per pound than the kitty brands. Next time we go to a feed store I’m going to check it out.
c) The urine soaked sawdust can be sent to the normal compost pile. The urine dust forms the majority of the waste material generated by the cat boxes. So I’m still composting say 80-90% of their waste, but with much less trouble.
(Note: It’s the poo which has the scary stuff in it, after all. If there’s any residual traces of scary stuff (that’s a scientific term, by the way) in the sawdust, carried along by microscopic pieces of poo, I don’t really mind, because between the cats bathing on our dining table, sleeping on our bed pillows, and the one cat that likes to stick his paw in my mouth, I’ve met all their bacteria and parasites already. And anyway, it’s all going to go through good long composting cycle.)
In sum, this is a good way to go for anyone who wants to recycle at most of their cat litter.
The weak spot, of course, is the poo. The poo can go in the toilet or into the garbage. Even with three indoor cats, day to day this doesn’t amount amount to all that much.
I understand that sea lions are impacted by toxiplasmosis, which is why I don’t flush our cat poo. I don’t know how much this caution is worth, actually, considering the staggering amount of cat poo is laying around in yards and parkways all over Los Angeles, ready to roll down the storm drains with the next rain. But nonetheless, as of now I send their poo to the landfill.
It’s a compromise. I’m pretty happy with it.
DIY IDEAS: Some preliminary notions that I considered: Make sure you have enough clearance between the lower and upper box. You’ll want at least two inches to accommodate the dust. You need tons and tons of holes on the bottom of the inside tray for it to work correctly. It might be difficult to balance the structural integrity of the floor with a sufficiency of holes. And speaking of structural integrity, the bought boxes have many little legs on the bottom of the inside tray to keep the tray firm under the feline foot. You’ll need to improvise some sort of support to keep the floor from sagging.