How To Compost Cat Litter

Composting cat litter is a great way to become more eco friendly. It can be a greener way to dispose of used cat litter, and the finished compost will provide you with free fertilizer for your household plants.

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If done correctly, composting your cat’s litter can really be a great win for the environment. Since so much cat litter is used each year, keeping it from ending up in the landfill is a big plus.


Before you decide if you should compost your cat’s litter, there are a few important things to consider. This includes your cat’s lifestyle and what cat type of litter you use. Your cat’s lifestyle is surprisingly a deciding factor when it comes to composting cat poop.

Can you compost cat poop?

Composting cat poop is controversial, because it could contain a parasite called Toxoplasma gondii. This parasite can have a negative effect on the health of humans and wildlife. You can read more about this issue here.

Lifestyle and diet

Not all cats carry T-gondii , so this is where your cat’s lifestyle comes into the picture.

Cats usually become infected due to hunting, so if your cat is an indoor cat, composting the cat poop should be ok. An exception to this is if you feed your cat food that contains raw meat. Your cat needs to have been indoors for at least two weeks before you start the composting process.

Disposing of cat litter in the State of California

In the State of California, it is illegal to flush cat litter because of T-gondii. The purpose of this is to prevent the parasite from ending up in water that is the natural habitat of sea otters.

Below you can read a quote from California Legislative Information (

The Legislature finds and declares that several types of nonpoint source pollution are harmful to sea otters, and that scientific studies point to links between cat feces, the pathogen T-gondii, and sea otter mortality.

Click here to read the complete legislation. It also aims to encourage “properly disposing of outdoor cat feces” and keep it from entering gutters or storm drains.

Even though you are not technically “flushing” cat litter if you are composting it, it is best to simply not do it. There is still a risk that it could get to sea otter habitat, and pose a risk to the wildlife living there.


Compostable cat litter

Not all kinds of cat litter can be composted. For the composting process to work, the litter needs to be biodegradable. Clay and silica based cat litter do not fall into this category, and and are not suited for this purpose. Below is a list of some natural alternatives that can be composted – that also happens to be more eco friendly.

Biodegradable cat litter:

  • Wood pellet cat litter, and other wood based litter options
  • Grass seed cat litter
  • Wheat cat litter
  • Coconut cat litter
  • Corn cat litter
Biodegradable cat litter that is compostable

Can clumping cat litter be composted?

The same applies to clumping cat litter as non-clumping litter. Clumping is not a problem, as long as the cat litter is biodegradable, and does not contain clay or silica.

Step by step cat litter composting guide

For a beginner, the easiest way to start composting cat litter is cold composting*. Cold composting means that the compost does not need to reach higher levels of heat to decompose. This is also the most passive form of composting.

*If you live in an apartment, or do not have access to a backyard, the bokashi method would probably be the best option for you. More information about composting cat litter with bokashi can be found in the book The Pet Poo Pocket Guide by Rose Seemann.

Supplies for composting cat litter

You will need:


How to compost cat litter using the cold composting method

  • Set up your composting bins.
    • Place the small bin close to the litter box for conveniency. This way, it will be easy to scoop the used litter right into the container when cleaning the litter box.
    • The larger composting bin should ideally be placed in an outdoor location. If you have a yard or a balcony, those are great options.
  • Cover the bottom of your small bin with brown materials (shredded paper, cardboard or sawdust).
    • Add more brown material after adding new used litter. This will help with odor control.
  • Cover the bottom of your larger bin with garden soil. Next, add a layer of brown material, ideally cardboard or sawdust. Now the large bin is ready to start the composting process.
    • Add a layer of green material (see supplies section).
    • Add a layer of brown material on top of the green one.
    • Add a layer of soil on top of the layer of brow materials. Putting the soil on top will help with odor control, and keep animals from taking an interest in your compost.
  • Empty the used cat litter from the small bin into the larger bin as needed.
    • Add fresh layers of brown material and soil on top of the cat litter each time.
  • To help with the decomposition process in the large composting bin, you need to aerate the compost.
    • You do this by stirring the compost 1-2 times per week. For example when you add more cat litter from the small bin.

A well balanced compost should not smell bad. The compost should feel moist as a sponge, but not wet. If it is too dry, you can add some water to it. If the compost is too wet, you can add more brown material such as shredded paper into the mix.

How long does it take for cat litter to decompose and turn into compost?

Using cold composting process for the used cat litter, you should expect it to take at least a year. Hot composting could take only a few months, but you will have to put a little more effort into the process.


What can you use the finished compost for?

An added benefit of making your own compost, is that it can be used as a fertilizer. However, since you will be composting used cat litter, you should not use the compost for edible plants. A good way to use the finished cat litter compost, is as a fertilizer for plants in flower pots or raised garden beds.

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