Can Kitty Litter and Dog, Bird, or Guinea Pig Waste Go Into Compost?

Things You Can Compost

Compost can include just about any organic thing, such as:

• Landscaping: plant material like grass, leaves, wood chips, branches (shredded finely), sawdust from untreated lumber.
• Kitchen waste: crushed eggshells, coffee grounds, teq bags, peels of fruits and vegetables, rinds from melons, strawberry tops, etc.
• Shredded paper: tissues, napkins, newspaper, non-glossy typing paper, cardboard without a waxy finish.
• Human and Animal material: clipped nails or trimmed hair or fur, as long as it isn’t bleached or artificially colored.
• Natural cloth: 100% wool, cotton, linen, silk, or other natural fabrics can be composted. Remove any buttons or zippers and shred the cloth to speed up decomposition.

Things You Shouldn’t Compost

You don’t need to be told not to try to compost metal, plastic, chemicals, or other non-organic things. But even some organic things should be avoided. Here are some examples:

• Meat, bones, and grease as they can carry disease and attract foraging animals.
• Food wastes like eggs and dairy that will smell bad as they decay and draw vermin from long distances.
• Materials that are treated with chemicals, such as artificial fabrics or pressure-treated lumber used in decking.
• Plastic or styrofoam containers marked “compostable” or “biodegradable.” These usually need to be broken down in an industrial facility. They will not easily decompose in a small home compost pile.
• Diseased plants or seed-bearing weeds. Whatever goes into your compost will end up in your garden. You could be creating a much bigger problem for yourself.

The Problem With Poo

Of course animal manure of all species is completely organic and biodegradable, so you can put any kind of animal waste you want to in your compost. But just because you can do something doesn’t mean you should do it. There are some really good reasons not to try to compost animal waste:

• It smells bad.
• It can attract vermin.
• It can transmit disease.

On the positive side, feces can be rich in nitrogen and potassium and they can help increase the heat level and pace of decomposition in your compost pile. But if you’re going to do it, you have to take some precautions to do it safely.

Preferred Pet Poo for Compost

Animals that eat meat can catch and transmit diseases from the creatures they eat. Herbivores are far less likely to pick up dangerous pathogens from their food. That means the best types of pet manure for your compost will come from these animals:

• Rodents such as hamsters, gerbils, rabbits, guinea pigs, chinchillas, mice, or rats.
• Grazing livestock like horses, cows, llamas, sheep, goats, etc.

Layer the manure between other composted materials like sawdust, grass clippings, and vegetable scraps. Turn the compost regularly to aerate it. If the compost pile gets enough oxygen, it will not have as strong an odor.

Avoided Pet Poo for Compost

Beginning composters should avoid including waste products from omnivores or carnivores. If this kind of waste is not handled properly, it can transmit serious diseases. For example, pregnant women and people who are immunocompromised can contract toxoplasmosis from cat feces. Dogs can transmit roundworms that are not always killed in the composting process. Reptiles carry Salmonella bacteria in their intestinal tract, which can spread to humans through feces and cause serious illness. So these are examples of pets whose waste is better put in the garbage:

• Carnivorous mammals like cats and dogs.
• Omnivores like pigs and ferrets.
• Reptiles such as snakes and lizards.

If you do decide to use this kind of waste, carefully follow safety procedures and guidelines, which we’ll discuss shortly.

Birds and Fish

Birds do carry some pathogens that can pass to people, so that means their manure is not a danger-free additive to compost. Birds are also a major transmitter of seeds because they often poop out undigested seeds that will sprout where ever they end up. That’s why you often find a variety of weeds and bushes along fence lines where birds perch. However, many people do compost not only indoor bird manure, but the muck from their backyard chicken or duck coops.

As for used aquarium water, if you have a saltwater tank, you don’t want that salt in your compost. Just pour it down the drain. Water from a freshwater tank is full of nitrates and can be a healthy additive to a well-drained pile.

Baking Germs in Hot Compost

Maintaining the right temperature is the key to safely composting animal manure. The pile needs to be 1 cubic yard at a minimum to generate a high enough temperature. Nitrogen-rich materials, such as manure, will heat it up. You’ll want to use a thermometer to monitor when the pile reaches 141-155 °F, the temperature at which weed seeds and disease pathogens will die. This temperature should be maintained for a week or more. However, when the temperature reaches 160 °F, it needs to be cooled off by turning the pile. Otherwise, a sustained high temperature will kill beneficial microbes and stop the decomposition process.

Using Manure-Based Compost

Clearly, there is room for error here, so your compost pile might not kill all the bacteria it should. This is why compost containing manure should be turned and decomposed for 6 months to a year. And this is also why you should not use compost with pet waste on any kind of food plants in your garden. Use it strictly for your flowers, shrubbery, trees, and other ornamental plants.

So the bottom line is, yes, you can compost any kind of pet manure. Waste from herbivores is safer than waste from carnivores. Any kind of manure-based compost should be carefully monitored at a high enough sustained temperature to kill pathogens but keep helpful microbes alive. And just in case something survived that shouldn’t, don’t use manure-based compost on edible plants.