Can I Put Compost in My Tortoise Table?

Putting together your tortoise’s enclosure involves a lot more decisions than you may have realized! One of the most important decisions to make is what kind of substrate to use. If you’re trying to go the natural route, it can be particularly difficult to figure out what materials you can and can’t use in your tortoise’s environment.

So can I put compost in my tortoise table? While compost that hasn’t been chemically treated can be used as a substrate, compost that has been treated should not be used due to its toxic nature.

Read on to find out more about substrate and how you can use compost. You’ll also learn about the pros and cons of several kinds of substrate, as well as which types to avoid at all costs. 

What Is Substrate?

Substrate is similar to bedding. It covers the bottom of your tortoise’s enclosure and provides a surface for it to dig into and burrow under. It can also help to maintain your pet’s health while increasing the humidity and temperature of the enclosure.

Substrate affects your tortoise’s shell, skin, and breathing, so it’s definitely something you’ll want to learn more about!

What Are the Benefits of Substrate?

Substrate is a very important aspect of your tortoise’s environment! Not only does it make your tortoise’s enclosure look nicer, but it provides them with plenty of benefits. Tortoises often dig in the wild, and substrate gives them an opportunity to engage in this natural behavior.

Another upside to using substrate is that it makes your pet’s enclosure a lot easier to clean up. It can also help to regulate humidity, provide warmth, and keep your tortoise healthy.

Using Compost as Substrate

One thing to avoid is using compost packaged as “potting compost,” because it contains pesticides that can be harmful to your tortoise. However, some experts recommend creating a “bioactive substrate system,” which is very similar to a compost pile. 

A bioactive substrate system has some great benefits, like maintaining a humid environment in your tortoise’s enclosure and easily breaking down waste. You can create this kind of substrate system by layering the following items:

  • 1 inch of broken lava rocks
  • 4 inches of soil mix
  • A top layer of palm leaves or cypress

When creating this kind of substrate, it’s important to make sure that you have a way to check on and maintain the water level. It’s also a good idea to add earthworms and live plants. You can add additional compost to the substrate if you’d like, but be careful–compost can be an ideal host for mites.

Common Tortoise Substrates

There are definitely a lot of options when it comes to substrates for your tortoise table! Here are several of the most common types.


Many tortoise experts consider soil the ideal substrate for tortoises in captivity, as long as it doesn’t contain any pesticides or fertilizers. Sterilized soil is especially beneficial to your tortoise.

This is because it is heat treated to kill off fungus and bacteria. Soil is a great natural choice, and it’s fireproof. It makes a good surface for walking, but is also perfect for digging and burrowing.

One downside to using soil as substrate is that it can get muddy as moisture builds up. A way to fix this issue is to mix the soil with peat moss, which is great for absorbing moisture.

Plus, peat moss won’t cause any danger to your tortoise if eaten. Another negative point is that if the soil becomes too dry, it creates a lot of dust. Additionally, organic soil can have a strong scent and contain feces from other animal species. 

Coconut Coir

This finely ground coconut husk substrate is natural and doesn’t have any kind of negative effect on the environment. It’s lightweight, easy to store, and is very affordable. The downside is that there are tons of different brands that sell coconut coir, and each brand’s product differs in many different areas.

This means it will be important for you to find a brand that works for you and your pet, and to realize that if you buy from a different brand, you’ll have a very different kind of substrate on your hands.

If you don’t keep the right level of humidity in your tortoise’s enclosure, coconut coir can become dehydrating. On the other hand, if it gets too wet, it can cause a nasty odor. You’ll also need to take special care to keep it out of your tortoise’s food and water bowls. Since it’s so lightweight, it can move around the enclosure easily.

Coconut Chips

Although similar to coconut coir, coconut chips vary in a few ways. They’re coarser and heavier, providing a better walking surface than coconut coir. They’re also less likely to make their way into your pet’s food and water bowls. Just like coconut coir, coconut chips are lightweight and easy to store. 

One huge benefit to using coconut chips as substrate is that they can be reused after sanitizing them in boiling water. They’re also very absorbent, so if you want to increase the humidity in your tortoise’s enclosure, adding some water to the coconut chips will do the trick. However, they can sometimes stain your pet’s skin an orange-brown color, and if they’re kept dry, a lot of dust will build up. 

Sphagnum Moss

Sphagnum moss is a very popular substrate that’s commonly used with baby and juvenile tortoises–but one thing to keep in mind is that you’ll have to change this type of substrate more frequently.

Because it’s so moist, fungus growth can happen very quickly. If your tortoise loves to burrow and dig, sphagnum moss is great because it creates very warm and humid hides. Similar to coconut chips, it can be boiled and reused.

However, sphagnum moss is on the pricier side compared to other substrates, and it can cause health issues for your pet if it gets too dry. It can contain fungi, including a type that causes a chronic skin condition in humans.

For this reason, if you choose to use sphagnum moss for your tortoise’s substrate, it’s a wise choice to invest in the highest quality to avoid issues with fungus. 

Peat Moss

Peat moss also comes from the sphagnum plant, but it’s a completely different product. While sphagnum moss is the living moss that grows on top of a sphagnum bog, peat moss is actually the dead material that stays at the bottom of the bog. It’s much cheaper than sphagnum moss and doesn’t contain fungus that can cause human skin conditions. 

This type of substrate is best when mixed with others. By itself, it’s very fluffy and difficult to wet initially. It also dries out pretty quickly. But when combined with other types of substrate, it can help absorb moisture and create a better texture and digging opportunities for your pet.

Substrates to Avoid

These are some substrates to stay away from!

  • Calci-Sand: This substrate, although sometimes used in pet stores, is not recommended! It can be very dehydrating for your pet. If ingested, it can cause dangerous or even fatal gut impaction. It can also cause eye irritation because of the dust it produces.
  • Alfalfa Substrates: Sometimes referred to as rabbit pellets, this type of substrate is extremely high in calcium and can be dangerous to your tortoise if eaten. It can also be dehydrating and cause eye and respiratory infections.
  • Pine or Cedar Chips: These cause very serious health issues if your pet eats them, and they can also give off dangerous fumes.
  • Bark Chips: Bark chips often house mites and are typically fatal when ingested.
  • Paper Towels or Newspaper: Although commonly used, newspaper and paper towels just don’t provide the benefits that a good substrate does. They’re also very flammable, which can cause issues if your heat source is too close. 

How Much Substrate Should I Use?

It’s important that your tortoise can dig or burrow as it wishes, so a layer of about two to three inches across the entire surface of the enclosure is typically enough.

How Often Do I Need to Replace the Substrate?

Substrate should be replaced every two to three weeks, or more often if you notice that it’s very soiled. A clean enclosure is very important to your tortoise’s health and wellbeing, both physically and mentally! A dirty cage can eventually lead to health issues, so be sure to keep up with maintenance.


Generally, you can use compost as substrate for your tortoise as long as it hasn’t been treated with chemicals. Other good options include soir, coconut coir, coconut chips, sphagnum moss, and peat moss.

Some types of substrate to avoid are Calci-Sand, alfalfa substrates, pine or cedar chips, bark chips, and paper towels or newspaper. These can all pose potential health risks to your tortoise. 


I’m Devin Nunn, an average joe that just so happens to have a deep love and passion for everything to do with reptiles. Because taking care of them for the vast majority of my life wasn’t fulfilling enough, I decided to begin educating others about them through my articles. read more...