Crested Gecko UVB Exposure: Finding the Perfect Balance

As a crested gecko owner, you’ve probably heard conflicting advice about UVB lighting—some say it’s essential, others claim it’s completely optional. This confusion leaves many new keepers wondering: “Do I really need to add UVB to my gecko’s tank?” The truth is more nuanced than you might think. While crested geckos are nocturnal and can survive without UVB, recent research shows that strategic exposure to low-level UVB significantly boosts their health, coloration, and natural behaviors. Getting the balance right between duration and intensity is crucial—too little won’t provide benefits, while too much could cause stress. Let’s clear up the confusion and give you a practical, science-backed plan to optimize your gecko’s lighting setup without overcomplicating your life.

The Great UVB Debate: Optional or Essential?

You’ve likely encountered two extremes in the crested gecko community. On one side, veteran breeders claim they’ve raised healthy geckos for decades without any UVB lighting. On the other, modern reptile specialists insist UVB is non-negotiable. Both perspectives contain truth. Crested geckos absolutely can survive without UVB—they’re adaptable creatures that evolved in New Caledonia’s dappled forest light. However, “surviving” isn’t the same as “thriving.” Current research from institutions like Zoo Med Laboratories shows that controlled UVB exposure stimulates natural vitamin D3 production, which is critical for calcium absorption. Without adequate D3, even with calcium supplements, your gecko risks metabolic bone disease—a painful, often fatal condition. The key isn’t whether to use UVB, but how to implement it correctly for maximum benefit without overwhelming your nocturnal pet.

Understanding UVB Intensity: The 2-5% Sweet Spot

When we talk about UVB intensity for crested geckos, we’re referring to the percentage of UVB output relative to total light. Forget high-output bulbs designed for bearded dragons—your gecko needs gentle, forest-floor level exposure. Research consistently points to 2-5% UVB as the ideal range. Why this specific window? Below 2%, the exposure is too weak to trigger meaningful vitamin D3 synthesis. Above 5%, you risk stressing your light-sensitive gecko or causing eye issues. The Arcadia 5% Tropical or Zoo Med Reptisun 5.0 are gold-standard choices because they deliver consistent, measurable output within this range. Crucially, intensity isn’t just about the bulb—it’s about distance. Mount your UVB fixture 12-18 inches above the highest basking spot (as confirmed by multiple reptile care guides). Use a Solarmeter 6.5 to verify actual UV index at basking height; aim for 1.0-2.0 UVI. Remember: mesh screens block up to 50% of UVB, so if your enclosure has a screen top, you’ll need to position the bulb closer or choose a slightly stronger output.

Mastering Duration: Why 10-12 Hours Is Non-Negotiable

Duration matters as much as intensity. Crested geckos don’t need UVB “all day” like diurnal lizards—they require a precise photoperiod that mimics their natural environment. The magic number? 10-12 hours daily. This duration aligns with dawn-to-dusk light cycles in New Caledonia’s forests, where filtered sunlight penetrates the canopy for roughly half the day. Setting your UVB on a timer is non-negotiable—fluctuating light schedules confuse your gecko’s circadian rhythm, leading to stress and appetite loss. Start your timer at 8 AM to simulate natural sunrise. Never leave UVB on during nighttime hours; complete darkness is essential for proper melatonin production. Pro tip: position the UVB fixture on the same side as your heat source. This creates a “basking zone” where your gecko can choose to absorb UVB when they’re naturally most active (dawn/dusk) without overheating.

Practical Benefits You’ll Actually Notice

Wondering what difference proper UVB makes in real life? Here’s what attentive keepers report within 2-3 months of correct implementation:

• Vibrant coloration: Many owners notice richer reds and oranges in their geckos’ patterns as UVB enhances pigment expression
• Improved appetite: Better calcium metabolism means stronger jaws and more consistent feeding
• Natural behaviors: Increased climbing, exploring, and “perching” during twilight hours
• Healthier live plants: If you use pothos or philodendrons, they’ll grow more vigorously under proper lighting

Most importantly, you’ll avoid the heartbreaking signs of metabolic bone disease: rubbery jaw, bent limbs, or lethargy. Prevention is always easier than treatment—especially since MBD is irreversible once symptoms appear.

Setting Up Your UVB System: A Step-by-Step Guide

Ready to implement this? Follow these steps for foolproof setup:

1. Choose the right fixture: Use a reflective linear fluorescent tube (like Arcadia’s Forest 6%) rather than compact bulbs, which create uneven “hot spots”
2. Position strategically: Mount inside the enclosure (not outside mesh) 15 inches above the highest branch. Avoid direct line-of-sight from hiding spots
3. Pair with timers: Connect to a $10 mechanical timer set for 12 hours (6 AM–6 PM). Never rely on manual switching
4. Monitor temperatures: Place a digital thermometer probe under the basking zone—UVB shouldn’t raise temps above 78°F. If it does, increase distance
5. Replace bulbs every 6 months: UVB output degrades long before the bulb burns out. Mark replacement dates on your calendar

For screen-top enclosures, consider the Arcadia ProT5 Kit—it mounts directly to mesh and delivers consistent output. Avoid “daylight” LEDs marketed as UVB sources; they emit zero meaningful UV radiation. If budget is tight, start with a single Reptisun 5.0 tube covering half the enclosure—your gecko will naturally seek optimal exposure.

Debunking 3 Common UVB Myths

Before we wrap up, let’s demolish persistent misconceptions that could harm your gecko:

• Myth: “Nocturnal = No UVB needed.” Truth: Wild crested geckos get dappled UV exposure at dawn/dusk. Captive geckos miss this natural opportunity without supplementation.
• Myth: “Household windows provide enough UV.” Truth: Standard glass blocks 90% of UVB. Your gecko gets virtually nothing from sunlit windows.
• Myth: “More UVB = stronger bones.” Truth: Excessive UVB causes oxidative stress. Stick to the 2-5% range—more isn’t better.

Remember: UVB isn’t about replicating desert sun conditions. It’s about mimicking the subtle, filtered forest light your gecko evolved with. When done right, it should feel like adding a subtle background rhythm to their environment—not a glaring spotlight.

Final Thoughts: Balance Is Everything

Crested gecko UVB lighting isn’t about rigid rules—it’s about thoughtful balance. The perfect setup combines moderate intensity (2-5% UVB at basking height) with consistent duration (10-12 hours daily), all while respecting your gecko’s nocturnal nature. Start conservatively: mount a quality 5.0 bulb 15 inches above basking branches, set a timer, and observe your gecko’s behavior for two weeks. If they avoid the lit area, increase distance slightly. If they linger under the bulb at dawn/dusk, you’ve nailed it. Remember that UVB is just one piece of the puzzle—pair it with proper humidity, varied diet, and temperature gradients for truly exceptional care. Most importantly, trust your eyes over internet debates. A gecko with bright eyes, steady weight gain, and natural behaviors is your best indicator of success. By focusing on this delicate balance of duration and intensity, you’re not just preventing disease—you’re unlocking your crested gecko’s full potential for health and vibrancy. That’s the kind of care that turns a basic pet into a thriving companion for years to come.