How to Compost Your Cat’s Litter

As national awareness of a global ecological crisis is being risen, cat-and-dog-owners are looking for more and more ways to raise green pets. While composting your cat’s litter isn’t likely to turn him a freakish shade of olive-drab, this step-by-step guide can help reduce your cat’s ecological paw-print by disposing of his waste in a way that’s responsible and beneficial.

There are many benefits to choosing to compost your cat’s litter. His waste will no longer fill up plastic (petroleum-based) garbage bags, which reduces his carbon-paw-print more than you might initially expect. Even reusing bags from the grocery store to dispose of your cat’s waste will add up over time, since you might otherwise be using a canvas tote. Another obvious benefit of composting kitty-poo is that you’ll have a free, organic fertilizer, which won’t contain any synthetic contaminants and doesn’t need to be shipped across the country to get to your garden. Even if you don’t have a garden, odorless cat-compost can benefit your house plants, trees, or even your neighbor’s flowerbeds. Composting cat-litter is also a responsible way to keep potentially hazardous parasites and waste–like e. coli, toxoplasmosis, ammonia, and nitrate–out of our landfills and waterways.

There are four basic steps that need to be taken to turn your cat’s waste into a clean, odorless fertilizer that can enhance the nutrient-content, water-absorption capacity, and structural integrity of your soil.

1. Build, or Buy, a Compost Bin.

Compost bins that are pre-purchased can be used for disposing of cat waste, even if they were designed for food waste. The only critical difference in way that the two are composted is that cat waste must be left to compost for at least eighteen months before it is completely safe to use on edible crops. This eliminates the risk of parasites like e. coli, tapeworm, and toxoplasmosis contaminating foods grown in soil that has been enhanced with cat manure.

If you want to build your own compost bin, this is simple enough to do: layering several planks of wood, one on top of the other, to build an open-lidded box is all that’s really necessary. For one to two cats , a three-by-two-by-two foot box is generally sufficient space. You may not even need to nail the wood together; the purpose is to create a general container–not something that will be airtight. You may wish to place a lid on the bin to prevent dogs and cats from making your compost-bin their own, but it is not necessary for odor control if you compost properly.

If you have purchased a compost bin, follow the manufacturer’s instructions. If you have created one yourself, you can start encouraging the growth a healthy colony of compost-enhancing bacteria by adding a two-inch layer of topsoil, dry leaves, and/or sawdust to the bottom of your homemade bin.

2. Choose a Cat Litter.

Clay-based, sand-based, and crystalline litters are not compatible with use in compost, since they can damage your the structure of your soil and cause synthetic toxins to leak into your garden. The best choices for compostable cat litters are those made from natural, living sources.

Plain sawdust is a wonderful, inexpensive, and delightfully green cat litter that utilizes a wasted resource. Most cats love its texture and will eagerly use a sawdust-filled litterbox. However, it can sometimes be difficult to find in urban and suburban areas, and some owners may not be satisfied with the degree of odor-control it provides, especially if they own more than one cat or do not plan to empty the litterbox frequently. It is an excellent option if you have only one cat and don’t mind a bit of extra work.

Another good option for an earth-friendly and compostable cat-litter is a commercially produced litter made from pine or cedar. These tend to have pleasant, natural scents, and they have been processed in such a way as to be significantly more absorbent than plain sawdust. However, it is somewhat expensive by comparison.

Wheat-based natural litters are also a compost-friendly, green option for cat owners seeking a nontoxic and sustainable way to dispose of their cats’ waste. Composed of wheat husk–a by-product of the food-farming industry–they are an odorless, clean, and renewable option that is usually readily accepted by most cats and sufficiently absorbent, even for multi-cat households.

Another ecologically conscious option is litter made from recycled newspaper. Available in most stores, this product, while somewhat expensive, is accepted by most cats and composts very readily. Surprisingly, it is very absorbent compared to some other natural products, although the amount of odor control it provides for feces is somewhat limited.

You may find that you’d prefer to try all of these options to see what works best for you, your wallet, and your cat. Whatever you choose, these litters are all fully compatible with your choice to compost your cat’s litter, and can all help to enhance your soil.

3. Begin Composting.

The first time you compost your cat’s waste, it may seem unusual. Stick with it–you’ll soon be rewarded with the feeling that you’ve done your part to reduce the impact your cat is having on the planet, and you’ll act as a great example to people wishing to do the same.

After adding the first layer of sawdust, soil, or leaves, simply dump your cat’s waste (feces or urine-clumped litter) directly into your bin. Cover it with a one-inch layer of sawdust, soil, or leaves, and leave it alone. When the time comes to empty your entire litterbox, simply do the same, and add another layer of your composting material. To speed the composting process, it’s a good idea to aerate the litter every few weeks or months. Do this according to your manufacturer’s instructions, or, if you’ve built your own bin, simply turn the litter using a shovel or pitch-fork.

You may also purchase earthworms at a farm-and-garden supply store, or via the Internet. They can help to digest your cat’s manure and aerate it, speeding the compost process even further.

If you notice an odor coming from your compost bin, this is no reason to surrender hope. All that is necessary under these circumstances is that you add an additional layer of your compost material–sawdust is best. This will help to dilute the ammonia and seal in any offensive smells. Frequent aeration can prevent this problem from ever occurring.

When your compost bin is full, you can either continue aerating it occasionally, which will speed the composting process, or you can seal it at the top with a layer of straw, hay, or pine straw. This will lock in any odors and allow nature to do its work from there.

4. Use Your Compost.

After one year, or as little as six months if you continue aerating your bin, you can remove the top layer and use a shovel to check the status of your compost. Most likely, by this point, the manure will no longer be identifiable as cat litter, and will have a sweet, earthy smell and loamy texture. At this point, the compost can be used on ornamental plants and fruit trees, but you may want to wait a few months longer before using it on crops like potatoes, carrots, or peanuts, which it would directly contact–just to err on the side of caution.

By the time your cat litter has composted for eighteen months or more, it should be completely ready to use on any crop. Depending on your climate, soil composition, type of litter, and number of cats, you may not feel like the litter is completely ready. Although composted cat litter tends to be cleaner and less prone to parasites than typical garden soil (after all, you never know what’s been using your flower-bed as a litterbox!) many cat owners feel overly cautious about using litter to grow food crops. Although this fear is unfounded, there is nothing wrong with waiting another few months, or even years, before using your new compost.

There are many uses for composted cat manure. It can be used as a mulch for trees, or mixed with weak soil to give it a loamy texture and high nutrient content. It can be spread in flowerbeds to give extra life to your nitrate-hungry perennials. It can even be used as a starter for another compost pile, including kitchen compost!

Although cat-litter compost is safe, always use your common sense. Regardless of what kind of compost you use, it is always a good idea to wear gloves when handling compost or working in the garden. Pregnant women should avoid directly handling cat waste under any circumstances, since it sometimes carries a virus that may lead to birth defects in a fetus if it is contracted by the mother. Regardless of how your food is grown, you should aways wash and/or cook your vegetables before eating them; this rids them of both synthetic and natural contaminants.

It would be impossible to fully address the issue of composting cat manure without addressing what I refer to as the “gross-out” factor. How can someone grow food in their cat’s poop? you may be wondering. But the fact is that, regardless of where your food comes from, it was most likely grown in something you’d prefer not to think about. Conventional fruits and vegetables are often grown using massive amounts of petroleum-based fertilizers, and organic produce is almost always fertilized with chicken litter–a foul-smelling and highly pollutive mixture of bone, feather, tissue, and feces. It’s also worth noting that even your home-grown foods were grown in soil that was, inevitably, pooped in at some point by a wild or domestic animal.

With deliberately-composted cat litter, you can oversee the entire process that nature uses to turn one creature’s waste into another creature’s nourishment, and, in my opinion, that is a beautiful thing.

Written by Juniper Russo Tarascio – a freelance writer and natural health consultant living in the Southern US.

16 Comments Add yours

  1. Great post! Composting kitty’s litter including the poo recycles the organic matter back to the soil. This is an excellent example of the four Rs: rethink, reuse, reduce and recycle. By rethinking what type of cat litter to use, and how to dispose of it in an eco-friendly way, we move to reusing
    earth-friendly and compostable materials such as newspaper, sawdust, plant-based cat litters. This ensures we reduce kitty’s pawprint by not creating waste at the landfill. And when we compost the cat litter, we recycle all the organic matter back to the soil. That’s a purrfect loop!

  2. THOR says:

    Any suggestions for those living in apartments or otherwise unable to do such outdoorsey things like composting?

    1. Rosalind Newton says:


      Some suggestions: Find an eco friend willing to help take weekly litter to their suburban compost.

      At least use non chemical litter like cedar shavings , pine or newspaper. Save the bags it comes in to use in your garbage container and dispose of the litter. At least it is natural and you are not adding more chemicals to our earth.

      Start a business servicing eco-conscious city dwellers who have cats and other pets and interested in eco-friendly disposal. Could some organic farmers be interested in being part of this service?

      I wonder if there is a composting toilet for kitty litter?Maybe we should make one?

    2. Deborah says:

      Fortunately, I live where there’s curbside recyling, which includes a compostables bin. I use a biodegradable/compostable cat litter and biodegradable/compostable trash bags, such as Eco-Safe (from Natural Value) or BioBags.

    3. LIsa Moore says:

      Consider buying a Nature Mill composter, if you can. It speeds up the composting considerably and kills many of the micro organism in cat waste. I love it

  3. Great idea! I live in the city so I am not able to do your super sweet method of composting. Keep up the good work!

  4. Yzoldowl says:

    Composting does not kill toxoplasmosis spores. Just ask any nurse or animal health technician! It takes incineration to kill the spores. The ash is then a safe organic compound.

  5. nathania says:

    some people have said it is unwise to compost cat litter because of toxoplasmosis, do you know if the organism will die during composting?

  6. frl says:

    You are more likely to get toxoplasmosis from undercooked meat or vegetables than from your cat. If you cat is inside only and dewormed as necessary, there is minimal threat from toxoplasmosis.

  7. I’ve just begun my own adventure in composting litter, and linked to this post on my blog. Thank you for the useful information, especially about health concerns!

  8. I feel the best way to compose your cats litter is to get a self cleaning litter box. It really works wonders. Great Post by the way. I will be following your newest posts. Thanks

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