Bearded dragon lighting for multiple dragons

Three dragons of different ages in one room is actually a great setup — but it means you're managing three distinct lighting requirements simultaneously, and that's where things often go wrong. Bad lighting is the single most common husbandry mistake with bearded dragons: incorrect UVB output or basking temperatures lead to metabolic bone disease and chronic illness that owners frequently miss until real damage is done. To give you accurate schedules for each, I need a few things: what size enclosures are they each in, what UVB and basking bulbs are you currently using (brand and wattage for each), and how old are the three dragons?

Right, the compact Repti-Glo 10.0 bulbs are a real problem — compact fluorescents have a very narrow UV gradient and drop off quickly with distance, so in a 4x2x2 enclosure the dragons are almost certainly not getting adequate UVB across most of their usable space. The unbranded basking bulbs concern me too, since inconsistent wattage means you can't reliably hit the temperatures you need. Before we get into schedules, you need a UVB upgrade across all three. For a 4-foot enclosure, the Arcadia T5 HO 12% Desert 46cm kit is the correct choice — it's a linear T5 tube mounted at the top of the enclosure and it produces a reliable, measurable UV index across a wide area. The 12% output is appropriate for all three dragons regardless of age. Now, on the schedules: the 4-month juvenile needs 14 hours of light with a basking spot of 105–110°F. Your 18-month sub-adult needs 13 hours at 100–105°F. The 4-year adult needs 12 hours at 100–105°F. All three should drop to complete darkness at night — no red or blue night bulbs.

I understand the appeal, but I'd hold the line on the juvenile's longer photoperiod. Young dragons are growing fast and the extra light hours support appetite, activity, and calcium metabolism at a critical stage. Shortening it to match the adults could slow development. The one shortcut that genuinely works here: put all three on plug-in timer sockets and set each to the correct hours. After day one, there's no ongoing effort. Mechanical or digital timers both work fine — just make sure each enclosure has its own timer so you can adjust individually if health changes require it.

Household incandescent or halogen bulbs work perfectly well for basking — you don't need to pay a premium for reptile branding on a heat bulb. What matters is hitting the right temperature at basking spot level, not what's printed on the box. Get a decent digital thermometer with a probe or an infrared temperature gun and measure the actual surface temperature where the dragon sits, not the air temperature. Adjust the wattage up or down until you hit the targets I mentioned. A 75w or 100w PAR38 halogen flood is a good starting point for a 4x2x2. The UVB, though — that is absolutely where brand and specification matter. Don't compromise there.

It counts for mood and natural rhythm cues, but not for UVB — glass filters out virtually all UVA and UVB, so window light doesn't replace the tube. What it can do is cause problems if the enclosures are in direct sun: glass tanks heat up fast and you can cook a dragon very quickly without realising it. Make sure none of the three enclosures are in a position where direct sunlight hits them during the day. Ambient room light from a window is otherwise harmless and the dragons will track it naturally, which is fine alongside their controlled lighting schedule.