Substrates for Tortoise Enclosures
- Stars & other small, dryish area species -
Coconut coir mixed with some organic soil is my favorite indoor substrate. Soil adds some texture to the otherwise fluffy coco fiber. This mixture holds it shape when damp and allows female tortoises to nest successfully.
The box above is a temporary nesting box for Goldens. They live outdoors year round, but I do bring them in during bad winter storms.
So many choices
The choice and condition of substrate is important because your tortoise spends most of his time on it when indoors. If it's too wet, he can develop shell rot, respiratory infections, and other health problems. If it's too dry, he can become dehydrated. And if you have asthma or allergies, it must be something that doesn't make you sick!
What works well for one tortoise keeper, may not work in another person's setting. You'll need to adjust your care and substrate choice based on your tortoise species, type of indoor setup, room humidity, and room temperature level. There is no one "best" substrate that works for everyone.
Soil & soil mixes
Plain garden soil, with no additives like fertilizers or perlite, is the most natural substrate for indoor tortoise pens. Soil can be used by itself or mixed with with other substrates like coconut coir or peat moss. Play with the mix to find the ratio you like best.
Pros of soil:
- natural substrate
- can be mixed with other substrates
- when packed down, provides a good walking surface
- is diggable, tortoises can bury themselves and dig nests to lay eggs
- when kept moist, provides a humid microclimate for burying species
- is fireproof
Cons of soil:
- can be very dusty when dry
- turns into messy mud if too wet
- can contain fertilizers and perlite
- can contain unwanted bugs, parasites, and their eggs
- organic soils contain animal feces like chicken droppings and bat guano
- organic soil can have a strong, musty, rotting smell
- organic soils can contain aromatic wood shreds/chips of unknown type, these can irritate tortoises and allergic keepers
Be cautious of sand
Using sand indoors is controversial. Many keepers have used it for years in indoor substrate mixes with no problems, while others claim it should never be used because it can be accidentally swallowed with food.
Straight sand by itself is NOT recommended. The traditional indoor substrate formula is to mix plain soil with a small amount of play sand. This mix has worked well with burrowing species like Greeks.
Caution! Accidental substrate ingestion with food and (possible) following impaction is a danger with ALL loose substrates, but especially with sand because it's heavy and can collect in the intestinal tract. You should exercise care to keep your tortoise's food substrate free regardless of what substrate you choose.
Popular indoor substrates for tortoises include coconut coir, soil & coconut coir mix, organic soil, and peat moss.
Popular chip type substrates include fir / orchid bark, cypress mulch, and coconut husk chips. Also shown is sphagnum moss which is very soft when damp.
Coconut husk substrates
Coconut husk products are sold as small animal substrates, reptile substrates, soil amendments, and planting mediums. Many are cleaned and prewashed before packaging. The exact texture and composition of coconut husk products varies by the company, but below are generalized descriptions of the various types. Coir and chips are the most commonly available formats. Many sellers use the terms "coir" and" fiber" interchangeably for the finer ground husks.
- Coir = finely ground in texture
- Fiber = fiber strands, wiry in texture
- Chips = chunky pieces; available in small, medium, and large sizes; chip sizes range from about ¼" to 1"
- Shredded chips = fluffy, fibrous, and stringy in texture; not as chunky as chips, but softer in texture
Allergy wise, coconut husk coir substrate is one of the least irritating indoor substrates. It is available in loose or compressed form. When wet, this finely ground coconut substrate resembles coffee grounds. The expandable coconut coir is the cheapest. It comes as a compressed brick that will multiply in volume when soaked in warm water.
The quality of coconut husk products varies by the company. Some products are ground finer (coir) while others are coarser with longer fiber "hairs" (fiber). Some are almost odor free, while others smell more. Try different brands to see which one you like the best.
Coconut husk coir / fiber is sold under many different product names, including compressed coco coir, coco peat, organic growing medium, and wonder soil. Just check the package labels to confirm the contents are plain coconut fiber with no additives.
Pros of coconut coir:
- natural product
- no negative impact on the environment
- very popular, easy to find in stores
- very light weight, packages are easy to carry and move
- compressed blocks are easy to store due to their small size
- compressed blocks are economical even in larger enclosures
Cons of coconut coir:
- quality, texture, particle size, and smell varies between brands
- very dusty when dry, can leave a layer of "shell dust" around the room
- can be dehydrating if kept dry
- when wet, can smell like musty leaves and dirt
- difficult to keep away from water and food dishes
- gets pushed around the enclosure easily because it's so lightweight
- can be very spongy when used by itself creating an unstable walking surface
- can make allergic person's skin itch
b.) Coconut chips
Coconut "bark" chips are the coarser version of coconut husk substrates. They are another popular indoor tortoise enclosure substrate choice because they are natural, nice looking, and easy to find.
Pros of coco chips:
- natural product
- easy to mix with coir or other substrates
- easier to keep out of water and food dishes than coir
- absorbent, can be wetted to increase humidity
- light weight, easy to move and carry
- slightly soiled chips can be washed with boiling water and reused
Cons of coco chips:
- can be dusty and dehydrating if kept dry
- when dry, can "suck" the moisture out of tortoises
- more difficult to wet than coco fiber, less absorbent
- when wet, can stain tortoise's skin orange brown
Caution! When I mention coco mulch, I am talking about cut and shredded coconut shells. I am NOT talking about cacao bean, aka cocoa, shell mulch. Cacao bean shell mulch is toxic to dogs if the chemical theobromine has not been removed from it. I only use coconut shell husk chips and coir, not cacao bean mulch.
Sphagnum moss
Sphagnum moss is a popular substrate for baby tortoises. If you do use moss, change it frequently because fungus growth and fungal spores in the moss can be a concern. Especially in cheaper, lower grade products.
I always buy the premium grade (AAA, 5 star), long fiber sphagnum moss from New Zealand for its quality and cleanliness. I use it in all my hatchling indoor enclosures and keep it slightly damp and warm. My babies love to burrow in it!
Pros of sphagnum moss:
- highly absorbent, can contain large amounts of water
- great for warm, humid hides
- great for hatchlings to burrow into
- slightly soiled moss can be washed in boiling water and reused
Cons of sphagnum moss:
- high grade moss is expensive (New Zealand long fiber is considered the best)
- when dry, it's very flaky and brakes into tiny pieces
- may contain long, stringy pieces that can wrap around babies neck or legs
- can contain fungi and fungal spores
- fungus Sporotrichum (Sporothrix) schenckii in moss can cause a chronic skin infection in humans called cutaneous sporotrichosis
- large scale commercial harvesting of sphagnum moss leads to loss of peat bogs, then plants and animals lose their native habitat, sphagnum regeneration is slow and can take decades
Expanding a 5 kg (11 lb) block of coconut coir. It took several buckets of water.
Expanding a 500 g (1.1 lb) block of compressed New Zealand sphagnum moss with water. It is very absorbent.
Sphagnum peat moss = peat moss
"Sphagnum moss" and "sphagnum peat moss" (peat moss), are both from the Sphagnum plant, but they are not the same product. Sphagnum moss is the living moss growing on top of a sphagnum bog. It has long strands and is green or light tan in color. Peat moss is the dead material at the bottom. Peat is medium or dark brown. Note that one has the word "peat" in the name and the other one doesn't.
Pros of peat moss:
- cheap
- according to the Canadian Sphagnum Peat Moss Association, there are no reported cases of Sporotrichosis caused by Canadian peat moss
- works best when mixed with other substrates
Cons of peat moss:
- when dry, it's very light weight and fluffy
- easily airborne and can irritate allergic person's nose, eyes and airways
- doesn't absorb water easily, hard to wet at first
- tends to dry out quickly under hot heat lamps
Wood chips & mulches
Wood chips and bark mulches are appealing looking natural substrates. Fir bark and cypress mulch are especially popular among tortoise keepers.
Pros of wood chips:
- natural product, looks nice, ready to use
- fir bark is easy to find, cypress mulch less so
- slightly soiled fir bark can be cleaned with boiling water and reused
Cons of wood chips:
- can cause serious intestinal blockages if accidentally ingested with food (be sure to provide a substrate free eating area)
- sharp, shredded wood pieces, like cypress, can pierce intestinal walls if ingested
- can harbor mold spores that can irritate tortoise's and sensitive person's airways
- can contain bug eggs, mites, and other parasites
- fir bark / orchid bark has a strong odor that can irritate allergy sufferers
- cypress mulch is smelly and splintery, can irritate allergics
- harvesting of cypress causes environmental damage
No more rabbit pellets or paper
Today, many tortoise keepers have moved onto more humid indoor setups, even for dry area species. Higher ambient humidity is especially important for hatchlings and youngsters. Hot and dry enclosures expose tortoises to various degrees of chronic dehydration (losing large amounts of water) which can lead to kidney failure and, in worst cases, death. Warm, damp substrate areas and/or warm, humid hides help prevent fluid loss. Tropical species babies can be kept in warm and humid vivariums.
Rabbit hay pellets and alfalfa pellets used to be popular indoor substrates for tortoises, but they are not recommended anymore because they are very drying, mold quickly, can cause infections, and may induce walking problems.
Similarly, paper has fallen out of favor as an indoor tortoise substrate because it's slick and not diggable. It's best suited for short term, temporary use. For example, in quarantine tubs, hospital tubs, or for brief, overnight stays indoors when no heating is required. Paper can also be used as a feeding "plate" to help keep food substrate free.
Problems with substrates
a.) Impaction
Eating large quantities of ANY substrate can lead to a potentially fatal intestinal blockage. Veterinarians have performed surgeries on severely impacted tortoises and other reptiles who have consumed excessive amounts of sand, coconut coir, wood chips, or bark chips.
In well hydrated, non constipated tortoises, a small amount of substrate usually passes through without problems. A fiber rich food will also help push any accidentally swallowed substrate along the intestines.
With all loose substrates, especially with sand and chip type substrates, it's best to provide a substrate free eating area to avoid accidental ingestion of bedding during feeding.
You can serve food on paper or place it on a large, shallow tray, plate, dish, or tile. Also, double plating, i.e., placing a small feeding dish on top of a larger plate, helps keep substrate away from food. Do not place food directly on any loose substrate.
b.) Walking problems
Coarsely ground bark with large pieces can create an unstable, difficult to walk on surface in the enclosure, especially for babies and young ones. Finely ground bark chips pack tighter making it easier for the tortoises to walk on it, but the smaller pieces are also easier to eat and swallow.
Smooth paper has a rather slippery surface. For subadult and adult tortoises, paper is ok for short term temporary use, but it's not recommended for small, developing youngsters. Any smooth and slippery surface can cause babies' back legs to slip out when they are moving about in the enclosure. This can lead to permanent gait problems, for example splayed legs. A tortoise with splayed back legs cannot stand tall on them. Rather, the legs are more or less spread out when the tortoise stands or walks.
Wet paper towels can be used for brand new hatchlings for a few days if babies have residual yolk sacs. Paper towels give enough grip for walking and can be dampened.
c.) Allergy problems for keepers
Most wood chips, mulches, and soil mixes give out odors that can irritate sensitive people's allergies. Of the loose substrates, dry coconut bark chips seem to smell the least, but they can be quite "dusty" right out of the bag. When wet, they tend to smell rather musty, too.
