Bearded dragon lighting at 12 months

Bad lighting is the single most common husbandry mistake with bearded dragons — incorrect UVB output or basking temperatures are responsible for metabolic bone disease and chronic illness that owners often don't spot until real damage has already been done. At 12 months your dragon is right in that sub-adult transition window, which means their UVB and basking needs are shifting upward from what worked at 8 weeks. To point you in the right direction: what size is the enclosure, what UVB bulb are you running right now (brand and wattage), and roughly how long has that bulb been in use?

Right, a couple of things to address there. First, compact UVB bulbs — even 10.0s — have a very limited UV output range, typically only effective within about 20–25cm. In a 4x2x2 that means most of the enclosure gets almost no usable UVB, and at 8 months that bulb's UV output will have dropped significantly even if it still looks bright. Second, 40°C basking is on the low end for a sub-adult — you want 42–45°C at basking surface level. Is she eating well, and have you noticed any softness in the jaw or limbs, or reluctance to move around?

The lethargy and slow basking behaviour are classic early signs of insufficient UVB — she may be spending more time trying to thermoregulate because she's not getting what she needs. The good news is this is very fixable. For a 4x2x2 at the sub-adult to adult stage, I'd recommend switching to the Arcadia T5 HO 12% UVB tube in the 54W/46-inch size. T5 HO tubes push UV much further into the enclosure — effective UVB depth of around 50–60cm — which is what you need in that vivarium footprint. The 12% output is right for the UV Index a sub-adult bearded dragon requires, and Arcadia tubes hold their UV output reliably for 12 months before needing replacement. You'll want to pair it with an Arcadia ProT5 controller and reflector kit if you don't already have one, as the reflector roughly doubles usable UVB at basking depth.

Yes, get that basking spot up to 43–45°C surface temperature — measure with a temperature gun, not a dial thermometer, as those aren't accurate enough. A 100W halogen flood bulb (standard hardware store PAR38 or similar) is the most reliable way to hit that without spending a lot. If your current basking bulb is a branded reptile heat bulb, you're likely overpaying for the same output. Keep the cool side between 24–27°C and make sure she has a proper temperature gradient across the full length of the viv. Once the new UVB is in, give her a week or two and you should see activity levels pick back up noticeably.

At 12 months you want to flip the ratio — adult bearded dragons should be roughly 70–80% leafy greens and 20–30% insects, not the other way around. High-protein insect-heavy diets at this age can stress the kidneys over time. Staple greens like collard greens, spring greens, and watercress are ideal. Dust feeders with a calcium supplement at every meal and a multivitamin twice a week — Repashy CalciumPlus LoD is a solid all-in-one if you want to simplify. Once the UVB is sorted and she's synthesising D3 properly, you'll likely find she's much more interested in food generally.