Good lighting is the foundation of a healthy reptile. Both leopard geckos and bearded dragons benefit from UVB, which lets them make vitamin D3 and absorb calcium. Without it, they're at risk of metabolic bone disease.
Watch: the top 5 confusing things about buying UVB
How much UVB does each species need?
UVB strength is measured as a UV Index (UVI) at the spot where your animal basks. You don't need to measure it yourself: the right bulb at the right distance gets you there, which is why UVB makers publish distance charts.
- Leopard geckos are most active at dawn and dusk and prefer low UVB, around a UVI of 1–2 at the closest point under the lamp, with plenty of shade to retreat to. A lower-strength T5 HO, such as a 5–7% tube in a reflector fixture, is a good match; our gecko kit uses a Zoo Med ReptiSun 5.0.
- Bearded dragons are desert baskers and need strong UVB, around a UVI of 4–6 at the basking spot. A 12% T5 HO bulb (like the Arcadia ProT5 Desert in our dragon kit) is a good match.
Setting it up
- Mount the UVB fixture over the warm side, alongside the basking lamp, so your reptile gets heat and UVB in the same place, just like sunlight.
- Distance is everything. Follow your bulb maker's distance chart and adjust the height of the basking spot to match. For our kits: the gecko kit's hood rests on the mesh with the basking ledge about 6–8 inches below the tube; the dragon kit's basking surface sits about 16–20 inches below the tube when it's mounted inside, or about 12–14 inches when it rests on the mesh.
- A mesh lid blocks roughly a third of the UVB, so a light on top of mesh needs to sit closer to the basking spot than one mounted inside. With a high-output tube over a low-UVB species like a leopard gecko, the mesh helps keep the level gentle.
- Keep a steady day length of about 12–14 hours, a little longer in summer and shorter in winter. A plug-in timer makes this automatic; our bearded dragon kit includes one.
- Skip colored or "night" bulbs. Reptiles need darkness at night.
Replace on a schedule
UVB bulbs keep glowing long after their UV output fades, and you can't see the difference. Most makers say to replace T5 HO tubes about every 12 months; we recommend every 10 months so your reptile never runs short. Write the install date on the bulb or fixture so you know when it's due.
Every animal is different. If you notice shaky limbs, a soft jaw or reduced appetite, see a reptile veterinarian.