Can You Compost Cat Litter? Is it Safe? And How to Do it

In the UK, 27% of all UK households have a cat. That’s more than 12 million cats.

As a result, every year, in the UK alone, cat owners throw away 2 million tons (or more than 100,000 truckloads) of cat litter, where it sits in landfills. Some even flush used litter down the toilet. Both of which are horrible for the environment.

Wouldn’t it be good, if when we cleaned our cat litter trays, we could do something else with it? Like compost it.

So in this article, we’ll cover;

Can you compost cat litter?
Why you should consider composting cat litter instead of throwing it in the bin
Safety considerations when composting cat litter
Where you can and shouldn’t use composted cat litter
How to compost cat litter

Can You Compost Cat Litter?

Yes, you can compost cat litter, but only certain types.

For composting to work, you need biodegradable cat litter. Clay and silica-based litters aren’t biodegradable and so you can’t compost them.

So What Types of Cat Litter Can I Compost?

There are plenty of types of biodegradable cat litter on the market, and you can compost them all. These include:

Wood pellets
Corn-based litter
Coconut-based litters
Paper litter
Other plant-based litters

Can I Compost Clumping Cat Litter?

Yes, you can compost clumping cat litter.

As long as it’s biodegradable and doesn’t contain clay or silica, you can compost it.

Why Compost Cat Litter Instead of Throwing it Away

When you throw used cat litter in the bin, it ends up in landfills. Where it sits on the surface until it’s covered by another layer of rubbish.

Now, lots of cat litter brands sell their products on the fact that they’re biodegradable. This means bacteria and other organisms break it down so it becomes a natural part of the earth again.

So we buy their products, thinking we’re doing our bit to help save the planet.

But this is what they don’t tell you…

When their biodegradable litter enters a landfill site, it doesn’t actually biodegrade.

See, for a biomaterial to biodegrade, it needs two things;

Oxygen, and
Water

Without them, it can’t happen.

There’s almost no oxygen amongst the layers of rubbish in landfills as they’re packed so tight. Instead of breaking down, it sits there, adding to our already huge pollution problem.

When you compost cat litter, you’re not contributing to this problem. You also give it a new purpose by using it to fertilise your plants.

Safety Considerations When Composting Cat Litter

Chances are your cat’s poo has been in the litter you want to compost. Some cat poo contains a parasite called Toxoplasmosis gondii. This can be dangerous for;

Pregnant women
People with weakened immune systems
Transplant patients
People suffering from AIDS
Very young or very old people

That said, a study in the British Medical Journal found that;

Risk factors most strongly predictive of infection [from Toxoplasmosis gondii] were eating undercooked lamb, beef, or game, contact with soil, and travel outside Europe and the United States and Canada. Contact with cats was not a risk factor. Between 30% and 63% of infections in different centres were attributed to consumption of undercooked or cured meat products and 6% to 17% to soil contact.
https://www.bmj.com/content/321/7254/142

So although contact with cats wasn’t a risk factor, it’s estimated that 6% – 17% of infections come from soil contact. And that’s where compost ends up, so so need to be careful about;

How you handle composted cat litter, and
Where you spread it

Where You Can (and Shouldn’t Use) Composted Cat Litter

To kill parasites and bacteria that might be in cat litter, the compost needs to be hot. You need to keep it at 60°C for at least 8 weeks.

So how you compost cat litter will determine;

How long to compost for, and
Where it’s safe to use it

Regular Composting

Chances are, a regular compost bin or heap won’t ever get hot enough to kill parasites and bacteria. You’ll also need to wait for 6 – 12 months for the litter to break down into useable compost.

In this case, don’t ever use it for growing vegetables or any other edible plants. Use it in your borders, pots and/or as a top dressing for your lawn.

Hot Composting

Hot composting uses a ‘Hot Bin’. This heats up to between 40°C – 60°C. Turning it up to 60°C will kill any and all bacteria and parasites in the litter. And it’ll create rich, useable compost in around 3 months.

This compost is free of harmful bacteria and parasites. As such, you can use it all over the garden, including your veggie beds.

How to Compost Cat Litter, Step-by-Step

Composting cat litter is like composting anything else. You can use a regular compost heap or bin or a hot box. The process is a little different, depending on the method you choose;

Cold Composting Using a Heap or Bin

This is the most common way of composting.

Make sure your compost heap or bin is big enough to turn it. One cubic metre or more is perfect.

Also, keep your compost heap or bin away from veggie beds.

Remove any and all cat poo as this is what contains parasites and bacteria
Add a layer of soil, leaves or sawdust as the bottom layer
Add a layer of cat litter
Add a layer of fruit, vegetable waste or grass clippings
Repeat this process as and when you’ve got material to add
Turn it every 6-8 weeks
Add a composting liquid, horse or chicken manure will help the process
After 6 – 12 months, your compost should be ready to use

Remember, don’t use cold composted cat litter in areas where you grow food. Only use it in borders planting pots etc.

Hot Composting Using a Hot Bin

A Hotbin will kill the bacteria and parasites contained in cat poo. Still, you should remove it to reduce contamination as much as possible.

A Hotbin will also produce compost much quicker than regular composting;

Remove any and all cat poo as this is what contains parasites and bacteria
Set your hotbin to 60 °C
Add a layer of soil, leaves or sawdust as the bottom layer
Add a layer of cat litter
Add a layer of fruit, vegetable waste or grass clippings
Repeat this process as and when you’ve got material to add
After around 3 months, you’ll have useable compost

Hot composting kills bacteria and parasites, so you can use it anywhere in your garden.

In Conclusion

There are 12.2 million cats in the UK. Cat owners send more than 2 million tons of used cat litter to landfill every year. Even biodegradable cat litter doesn’t break down in landfills.

By composting cat litter, you can turn it into a product you can use in your garden.

You can only compost biodegradable cat litter like;