Tarantula Enclosure Setup: Shape, Substrate, and a Humidity Debate

Tarantula enclosures are refreshingly simple compared to most exotic pets, no complex lighting, no elaborate temperature gradients. The details that do matter, though, matter quite a bit, especially enclosure shape and substrate depth.

Enclosure Shape and Size

Most commonly kept pet tarantulas are terrestrial, and the enclosure should be horizontal, wider than it is tall, specifically to limit fall risk. A reasonable adult minimum is around 20 by 10 by 10 inches, or roughly a 10-gallon tank, sized to about three times the tarantula's leg span. Keep the overall height low, under about 12 inches, since falls are a genuine danger for most tarantulas. An adult female Chilean rose hair spans up to about 6 inches across the legs and a curly hair about 6.5 inches, which is why three times the leg span lands close to that 20 inch floor.

Use a secure lid, but avoid mesh tops. A tarantula's feet can get caught in mesh and cause real injury. Acrylic with drilled ventilation holes is the better choice.

Substrate

Use at least 3 inches of depth, and more in a taller tank, since a deeper floor shortens the distance the spider can fall from the lid. Coconut fiber, peat, or organic pesticide-free soil all work well, they hold moisture appropriately and support natural burrowing behavior.

Furnishings

Provide at least one hide, cork bark, a half-log, or half of a terracotta pot all work. Add a shallow water dish, changed daily, and keep it shallow enough that there's no drowning risk.

Temperature

Room temperature, roughly 70 to 80°F, is fine for most homes with no supplemental heat needed, and most tarantulas stay comfortable anywhere from 70 to 85°F. If your space runs cold, use a heat mat mounted on the side of the enclosure, never the bottom, paired with a thermostat. A digital thermometer/hygrometer combo takes the guesswork out of both temperature and humidity at once.

Humidity

Published targets run from 40 to 60% up to 65 to 75%. Use the lower end for the dry-adapted species most keepers start with, like the Chilean rose hair, because ventilation matters more than humidity and stagnant damp breeds mold. The most consistent approach is a reliable water dish combined with lightly moistened substrate, using a fine mist spray bottle sparingly, rather than heavy misting, which raises mold risk without a clear benefit.

Arboreal Species: the Pink Toe

A pink toe lives in trees and bushes, and its enclosure turns the terrestrial rules on their side. An adult female Guyana pink toe grows to about 5 inches (13 cm), and males stay smaller at about 3.5 inches (9 cm). It gets a taller enclosure with vertical cork bark tubes and branches to anchor its silk retreat high up, since the height is for climbing.

Cross-ventilation matters more here than anywhere else. Holes on opposite sides keep air moving through the enclosure, because stagnant, humid air is what harms this species. Humidity runs higher than for a rose hair, about 65 to 80%, held by a shallow water dish and slightly moist lower layers of substrate. Airflow comes first, ahead of any humidity number. Keep it at 70 to 80°F like a terrestrial.

Lighting

None required. Most pet tarantulas are nocturnal, and bright light or direct sun should be avoided rather than added.

Diet

Feed live crickets or dubia roaches no larger than the tarantula's abdomen, and remove anything uneaten within 24 hours, a live insect left in the enclosure can injure or stress a tarantula, particularly one close to a molt. The invertebrate molting guide shows how to spot that premolt window coming.

Housing a Sling

A spiderling, or sling, does not go in the adult enclosure. A sling can be a quarter inch across the legs or less, small enough to vanish against the substrate, and in a big tank nobody can tell whether it is eating or molting.

• Container. Small plastic dram vials suit the tiniest slings. Deli cups are the usual home for any young tarantula: 16 oz for a terrestrial sling, which leaves room for a deep fill, and 32 oz for an arboreal one, which needs the height. Ventilate with two or three rings of small holes, every hole smaller than the spider's carapace, the hard plate over the front of its body, since a sling slips through gaps that look impossibly small.
• Substrate. For a terrestrial sling, fill at least two-thirds of the container with packed-down substrate, and push the back of a paintbrush in near the side to make a starter burrow. Keep it on the dry side of damp: a container that is too moist and stuffy is a death trap for a sling.
• Water. A sling of about half an inch or more gets a water dish whenever one fits, and the cap from a plastic water bottle is the usual first dish. Overflow it a little so there is a moist patch of substrate too. A sling too small for a dish drinks from a dampened corner of the substrate.
• Heat. Room temperature raises most slings, and many keepers hold them at 68 to 75°F with no added heat. They do not need 80°F or more.
• Arboreal slings. The taller 32 oz cup with an inch or so of substrate, and a piece of bark leaned at an angle against the side to climb and web against.

With a sling, tighten the 24-hour rule: never leave uneaten prey in overnight, since a cricket can attack and kill a molting sling. Guide a sling with a soft paintbrush, never by hand. Each step up to a bigger container is a small version of the adult catch cup and card move, with the brush doing the steering.

One Spider per Enclosure

House tarantulas singly. Most species are solitary and cannibalistic, cohabitation isn't a workable setup regardless of enclosure size.

Sources & Further Reading

Printable Guide

The Tarantula Care Package carries this setup as a checklist with the targets to hit, in a 49-page PDF you can keep by the enclosure, $8.99.

Read the first 5 pages free