Bearded dragon lighting for glass terrariums

Switching from a wooden vivarium to a glass terrarium is a bigger lighting change than most people expect — glass reflects and diffuses UVB differently to wood-backed enclosures, so bulbs and positioning that worked before may leave your dragon under-lit in the new setup. Bad lighting is honestly the most common husbandry mistake with bearded dragons: incorrect UVB or basking temps cause metabolic bone disease and chronic illness that owners often don't catch until real damage is done. To point you in the right direction — what size is the new terrarium, what UVB and basking bulbs are you currently running (brand and wattage), and how old is your dragon?

Good info — a 120cm enclosure and a 3-year-old dragon is a straightforward case, but the T8 is likely your weak point right now. T8 tubes produce lower UVB output than T5 HO tubes, and in a glass terrarium without the reflective wooden backing, you lose even more of that output before it reaches your dragon. For an adult bearded dragon in a 120cm glass setup, you really want an Arcadia 12% T5 HO tube running the full length of the enclosure, mounted inside the top of the terrarium or as close to the dragon as safely possible. What's the mesh situation on the lid — is it a fine mesh or more open? That affects how much UVB actually gets through.

Fine mesh can block 30–50% of UVB, which is a real problem. With fine mesh between the bulb and your dragon, a standard 12% tube starts behaving more like a 6–7% tube in terms of what actually hits him. There are two solutions: either mount the T5 unit inside the enclosure below the mesh, or step up to the Arcadia Dragon 14% T5 HO tube, which is specifically designed for bearded dragons and gives you enough overhead to compensate for mesh loss. I'd go with the Arcadia Pro T5 UVB Kit in the 1200mm size — it includes the 14% Dragon lamp and a reflector hood, which significantly boosts output. Paired with your basking spot at 40–42°C surface temp, that covers everything a healthy adult dragon needs. The kit runs around £60–70 on Amazon UK and is genuinely the correct tool for this setup.

It depends on ambient room temperature, but 100w in a glass terrarium often runs hotter than the same wattage in a wooden vivarium because glass retains heat differently. The target is a basking surface temp of 40–42°C measured with a temp gun directly on the basking spot — not an ambient thermometer. If you're hitting that, the wattage is fine. If it's running above 45°C surface, drop to a 75w. I'd strongly recommend picking up a cheap infrared temp gun if you haven't got one — digital dial thermometers are notoriously inaccurate for basking spots and will give you a false sense of security. The Etekcity 774 is about £12 on Amazon and is what most experienced keepers use.

Exactly right. Arcadia Pro T5 UVB Kit, 1200mm, with the 14% Dragon lamp — mount it inside below the mesh, position your dragon's basking spot so the top of his body is 25–30cm from the tube, and check that basking surface temp with a temp gun. That setup will give a 3-year-old dragon everything he needs. Replace the tube every 12 months even if it's still glowing — UVB output degrades well before the visible light does.