
Lane, the culprit, and his litter, World's Best.
If you google ‘cat litter composting’ and bother to read all of the forums, you’ll find a lot of opinions. A few people are actually doing it, some people are too afraid to even think about it, but there does not seem to be much in the way of extended experiments.
Our cat, Lane will henceforth be one of a very select few felines using a composting toilet (I don’t want to give too much credit to the toilet since it is me doing all the work, but for all intensive purposes. . .).
Our experiment, it being winter and all, will involve composting the cat poop, pee clumps and litter with the help of red composting worms from my current worm composting system. Worm composting, also known as vermicomposting, seems to make the most sense for this purpose because it can be done on a limited scale, it can be done indoors, and it can be added to on occasion, not being dependent on a large pile to create heat.

Here is my thumb on top of the kitty litter to give you and idea of the grit size.
The main concerns for cat poo composting involve Toxoplasma gondii, Toxocara cati, and fecal coliforms. As we continue with this experiment, we intend to pursue testing on the finished product within reasonable prices. Of course if it turns out the product is contaminated, we could limit the use of the compost to ornamentals or use a turkey oven bag to heat up the compost in the oven, sterilizing the resulting product.
World’s Best Cat Litter, our chosen litter, is made from corn and claims to be 100% organically derived and biodegradable. Click HERE to read part of the label. It is a good size grit, clumps well, keeps down smells, and is made from grain (I have noticed worms tend to love carbohydrates like pasta, bread, or rice, which leads me to think they will be fine with the litter). Other options could be Yesterday’s News, Feline Pine, Swheat Scoop, shredded newspaper, or any other organically derived litter.
We have an 18 gallon Rubbermaid tub for the project. I drilled eight large holes in the lid of the container for air exchange. Then I drilled two small holes at the center of one end of the bin for water drainage. To ensure the water drains to the container below, I tied a loop of plastic dental floss through the holes and let it drape into the container. The water will follow the floss down to where we want it. The bin is sitting up on a cardboard box to keep it from getting too cold and so the water can drain.
Like a space monkey being suited up, I prepped the worms for their maiden voyage. First, I balled up several pages of newspaper at the bottom, put in some finished worm castings (poop), and threw in a few worms. Then I emptied Lane’s kitty litter into the bin and poured water over the top to moisten the litter as best as I could. I topped the whole thing off with a bit more finished compost, some bad lettuce, a single orange peel, and a handful of worms. Click HERE to see what it looks like inside the bin.
I was going to call this blog Cat Crap Composting Conundrum, but Andrea liked this title better, I hope you agree.
We will continue to update the blog as the experiment progresses. Please share your ideas or opinions with us!
-Troy


I would be interested in your results- most likely for ornamentals. Since I have five cats, I am really interested in this project. I will look forward to updates.
I feed my cat mostly animal proteins, raw meats and such, because they are carnivores! What are your thoughts on this being introduced into the mix and what do you feed your cat?
That is an excellent question. Lane eats Science Diet Kitten. It is what the shelter was feeding him and we saw no reason to change his diet. The big scare about using carnivore crap seems to be in regards to the pathogens I mentioned in the blog. I have yet to see a citation concerning the persistence of these pathogens in the soil, away from the host animal.
In terms of meat products in general, people suggest they stay out of compost piles to reduce the chances of a dog or raccoon digging through the pile. These materials compost quite well in a hot pile. I had a dove crash into my back window and die last summer and I stuck her into a hot pile and within a couple weeks only the skull remained.
Conventional wisdom isn’t always right and must be tested. Check out this study done on composting dog waste: ftp://ftp-fc.sc.egov.usda.gov/AK/Publications/dogwastecomposting2.pdf
These are some of the reasons I think it is necessary to actually try these things out.
VERY interesting…I have 3 dogs and 1 cat. I feed them organically grown, hormone and antibotic free, raw meats and a small amount of high protein dry food. I always wondered why this could not be composted! I will read this in great detail, and maybe even conduct an experiment! Thanks,
I believe the pathegens will be destroyed at 155 degrees- How hot does a heap get? Clostridium perfringens die at about 165- do cat pathogens develop spores? spores can withstand anything. Keep us posted on your results.
I have done fairly extensive research on this very topic and would be happy to share the report if you’d like.
Yes, I would be interested in your findings.
how did this go? I would like to start this. did you find success and/or areas you had to alter your practices?