A millipede enclosure is mostly substrate, because in a millipede setup the substrate is also the food. Fill two thirds of the height with a mix built around crumbling rotten hardwood, top it with thick leaf litter, and hold humidity with a solid lid. Depth runs 4 to 10 inches by species.
That single fact separates a thriving millipede from one that slowly starves in a clean-looking tank. Everything else here is straightforward, and this guide covers sizing, the substrate recipe, sourcing wood safely, humidity, cleanup crews, and the maintenance rhythm that keeps a bin running for years.
Sizing the Enclosure
Millipedes need floor space more than height, and they are unbothered by company, so a group is easier than it sounds.
| Millipede size | Enclosure | Suits |
|---|---|---|
| Under 3 inches | 6 quart bin or 2 to 5 gallon tank | 2 to 3 animals |
| 3 to 5 inches | 12 quart bin or 10 gallon tank | 3 to 4 animals |
| 5 to 8 inches | 20 gallon long | 3 to 5 animals |
| 8 inches and up | 20 gallon long or larger | 2 to 3 animals |
Groups are fine. Millipedes are not territorial, do not compete aggressively, and breed more readily in company. Three or four is a better starting point than one.
Height is for substrate, not climbing. A tall tank is useful only because it lets you go deeper. Millipedes do climb glass and silicone, so the lid still needs to close properly.
Plastic bins work as well as glass and hold humidity better. A 12 quart storage bin with a few holes is a perfectly good millipede enclosure and costs a fraction of a tank.
Substrate: The Whole Build
Millipedes are detritivores. They eat decaying plant matter, and in captivity that means they eat their bedding. A millipede on plain coconut fibre is in an enclosure with no food in it.
Depth: 4 to 6 inches minimum, and 8 to 10 for large species such as giant Africans. Females also lay eggs in the substrate, so depth is a breeding requirement as well as a comfort one.
The mix:
- 3 parts crumbling rotten hardwood, well decayed
- 2 parts coconut fibre or peat
- 1 part organic topsoil, no fertiliser or perlite
- A generous top layer of dry hardwood leaf litter
The rotten wood is the food. It should be soft enough to crumble in your hand, the sort of punky white-rotted wood found inside an old log. Wood that still feels like timber has not decayed enough to be useful.
Pack it loosely rather than firmly. Unlike a burrowing tarantula or centipede, millipedes browse and shallow-tunnel rather than building structural burrows, and they benefit from a mix they can work through easily.
Top with leaf litter, several inches deep. Oak, magnolia, beech, and maple all work. The litter is food, cover, and humidity buffer at once, and its steady disappearance is the clearest sign your animals are eating well.
Sourcing Wood and Leaves Safely
Worth its own section, because this is where a good setup goes wrong.
Collect from hardwood, not conifer. Oak, maple, beech, hickory, and fruit woods are all suitable. Avoid pine, cedar, spruce, and anything aromatic, since the resins are harmful.
Avoid roadsides, farmland edges, and treated timber. Road salt, herbicide, and pesticide residue all persist in wood and leaves.
Take wood that is already decaying on the forest floor, not fresh cut. Look for logs that crumble when you press them.
Treating what you collect is optional and keepers disagree. Freezing for 48 hours kills most hitchhikers and is the gentlest option. Baking at a low temperature also works but destroys much of the microbial life that makes the substrate valuable. Many keepers use collected material untreated and accept the occasional unexpected arrival, on the basis that the microfauna is part of the point.
Commercial alternatives exist if collecting is not practical: bagged flake soil, prepared leaf litter, and decayed hardwood are all sold by invertebrate suppliers.
Humidity, Temperature and Ventilation
Most kept species want 70 to 80% humidity and 68 to 78F, which is normal room temperature in most homes. Desert species are the exception and want considerably drier conditions.
Moisture goes into the substrate. Pour water into one section until it is damp throughout, and let the rest stay moderately moist. Squeezed, the substrate should hold together without water running out.
Do not mist. It raises surface humidity briefly and does nothing for the substrate the animals live in and eat.
A solid lid with modest ventilation is the right balance. Millipedes need humidity held in, so a fully mesh top will dry the bin out within a day. Punch a modest field of pinholes high on two opposing sides for cross flow.
The failure modes are symmetrical. A bin that dries out causes millipedes to bury and stop eating, and prolonged drying kills. A waterlogged bin goes anaerobic, smells sour, and produces mites and mold. The gradient is your margin for error, since the animal will place itself where it suits.
Check moisture weekly by pushing a finger into a corner where nothing is buried.
Furnishings and Cleanup Crew
Cork bark laid flat gives daytime cover, and chunks of decaying wood on the surface serve as both hide and food.
A shallow water dish is optional in a properly humid bin, though it costs nothing and some keepers prefer having one.
Calcium, always available. Cuttlebone or crushed oyster shell on the surface, replaced as it disappears. Millipedes need it for their exoskeleton and use it heavily.
Skip live plants. They mostly get eaten or dug up.
Supplementary food goes on the surface, not mixed in. Small pieces of cucumber, courgette, squash, or sweet potato twice weekly at most, removed within 48 hours if uneaten. Overfeeding vegetables is the single most common cause of mite outbreaks in millipede bins, and a well-built substrate means the animals need very little beyond it.
Flake soil is worth knowing about. It is a fermented hardwood substrate developed for beetle larvae and sold by invertebrate suppliers, and it works well as a component of a millipede mix, typically replacing part of the rotten wood. It is more expensive than collecting your own but removes the sourcing problem entirely, and it is a reasonable option if you have nowhere safe to collect from.
Springtails and isopods are worth adding at setup. Springtails suppress mold in the damp section, and a small isopod population processes waste and leftover vegetables before mites establish. Dwarf whites tolerate the humidity well and stay out of the way. The two together make a millipede bin close to self-maintaining, which is part of why these enclosures are so low effort once established.
Maintenance
Weekly: check substrate moisture, remove uneaten vegetables, top up calcium if it has gone.
Monthly: add leaf litter as the previous layer disappears, and stir the top inch gently in an area with nothing buried.
Every 6 to 12 months: replace a portion of the substrate, ideally a third at a time rather than all of it, since established substrate holds microfauna the colony benefits from. Never dig deeply into a section where an animal may be molting.
Molting animals bury for one to several weeks and are soft and defenceless throughout. Do not dig, do not disturb the bin, and leave any shed exoskeleton in place, since it gets eaten for the calcium.
Long buried periods and slow leaf litter consumption are both hard to judge from memory, particularly across several animals sharing a bin. Logging surface sightings and litter top ups in InvertMate, our free invertebrate care app turns a vague sense that something is off into a record you can actually check.
Setup by Species Type
The build above suits most species, with three adjustments worth knowing.
Tropical species such as giant Africans want the deepest substrate, 8 to 10 inches, and humidity at the upper end. Details are in our guide to giant African millipede care.
Temperate natives such as the Texas gold need less depth, around 4 to 6 inches, and tolerate a wider temperature range. Covered in our Texas gold millipede guide.
Desert species are the outlier and want a genuinely dry setup with a small damp corner, not the humid build described here. Our desert millipede care sheet covers what changes.
General husbandry that applies across all of them is in our millipede keeping guide.
Common Enclosure Mistakes
- No rotten wood in the substrate. The commonest and most consequential error, since it removes the food.
- Substrate too shallow. Prevents burrowing and blocks breeding.
- Mesh lid. Dries the bin out within a day.
- Misting instead of wetting substrate. Feels like husbandry, achieves little.
- Waterlogged substrate. Sour smell, mites, mold.
- Conifer wood or leaves. Harmful resins.
- Collected material from a treated area. Herbicide and pesticide residue.
- Replacing all the substrate at once. Removes the microfauna that make it work.
- Digging to find a buried animal. Usually kills a molting millipede.
FAQ
How deep should a millipede enclosure be?
Four to six inches of substrate for smaller species and 8 to 10 for large ones such as giant Africans. Depth matters for burrowing, molting, and egg laying, so it is a breeding requirement as much as a comfort one.
What substrate do millipedes need?
A mix built around crumbling rotten hardwood, roughly three parts wood to two parts coconut fibre and one part topsoil, topped with several inches of dry hardwood leaf litter. The wood is food, not decoration, and a millipede without it slowly starves.
Do millipedes need a heat mat?
Usually not. Most commonly kept species do well between 68 and 78F, which is normal room temperature. If your home runs colder, use a low wattage mat on a side wall with a thermostat rather than underneath the enclosure.
Can millipedes live together?
Yes. They are not territorial and are commonly kept in groups, which also makes breeding possible. Three or four animals in a 10 gallon tank works well, provided the substrate is deep and there is plenty of rotting wood to go around.
How do I keep humidity up in a millipede enclosure?
Use a solid lid with modest pinhole ventilation rather than a mesh top, and add moisture to the substrate by pouring water into one section rather than misting. A mesh lid will drop humidity below a usable range within a day.
How often should I change millipede substrate?
Replace about a third every 6 to 12 months rather than all of it at once, since established substrate carries microfauna the colony depends on. Top up leaf litter monthly as it disappears, which is the animals eating it.
Track Your Millipedes with InvertMate
A millipede that buries for three weeks to molt and a leaf litter layer that vanishes over two months are both changes you notice only if you wrote something down. InvertMate lets you log surface sightings and molts, monitor substrate moisture and temperature trends, and set reminders for litter top ups and calcium checks. Free on the App Store & Play Store.