Because corn snakes are crepuscular/nocturnal, lighting beyond the natural cycle of the lights in your house/reptile room is not required.
However, because the light/dark cycle of your average house fluctuates from day to day, providing terrarium-specific lighting may be beneficial for regulating your snake’s natural biorhythms. Putting a low-wattage fluorescent bulb on a timer for 12 hours on/12 hours off should do the trick.
Wild corn snakes are occasionally exposed to UVB wavelengths during the day. It is not clear yet just how beneficial this exposure is, so generally speaking corn snakes do not require UVB lighting in captivity. However, if you would like to include UVB in your husbandry, select a high quality 5% UVB fluorescent tube and replace every 6 months.
Nighttime lighting such as a colored bulb is not necessary. Don’t waste your money.
Corn snakes are reptiles, which means that they are cold-blooded. Cold-blooded animals rely on their environment to provide the warmth/heat their bodies need for proper metabolism.
Perfect corn snake temperatures are on a heat gradient, with 3 temperature zones across the terrarium. This enables to the snake to move between zones as is comfortable.
- Basking zone: 85°F (29-30°C)
- Ambient: 78-82°F (25-27°C)
- Cool zone: 75°F (23-24°C)
Temps can safely fall to 70°F (21-22°C) at night.
The preferred method for maintaining these temperatures is with a heat mat. Heat mats are preferable to heat lamps because they can produce warmth without light, as well as provide belly heat, which is generally more useful to snakes than heat coming from above (ie heat lamps).
Choose a high-quality heat mat that will cover about ¼-1/3 of the terrarium’s floor space. This will facilitate the necessary heat gradient. If you find that you’re struggling to keep the cool end warm enough, use another small heat mat programmed to a lower temperature.
Heat mats can only be safely used if paired with a thermostat, a device that regulates how hot the mat gets. These range in quality and price (lower price usually means lower quality), but if you only have one or two snakes, many keepers recommend the Jump Start MTPRTC Digital Controller as a decently reliable option for just $20.
I also recommend spending $20 on a temp gun like the Etekcity Lasergrip 774 for instant temperature readings anywhere you point it. (Don’t bother with a sticker or gauge-type thermometer — they’re useless.) Some people prefer using a probe-type thermometer instead, but c’mon, it might be the American in me but it’s a temp GUN!
This is one of the big reasons why it is important to set up your enclosure at least a week before bringing your corn snake home — getting corn snake temperatures in the right place can take some fiddling around.
DO NOT USE HEAT ROCKS!
Heat rocks (also known as hot rocks/rock heaters/etc.) are manufactured and distributed under the same premise as an electric blanket — convenient heat whenever your reptile needs it. Sounds like a great idea, right? However, heat rocks are notoriously unreliable, and many a reptile has lost its life due to severe burns caused by these devices. Additionally, they’re not a good choice for heating your enclosure, as it only warms the rock’s surface, not the surrounding air.
Corn snakes thrive between 40-50% humidity. Correct humidity levels help maintain respiratory health as well as facilitate proper shedding.
Most corn snake keepers should be able maintain correct humidity with good substrate, a large water bowl, and little other effort. However, those who live in particularly dry climates may need to supplement this by placing the water bowl on the warm side of the terrarium (as opposed to the cool side) and misting as needed.
Keep track of your corn snake humidity levels with a hygrometer. My personal favorite is the Zilla Digital Thermometer-Hygrometer.
PRO TIP: If you are using a wood or melamine terrarium, place the heat mat INSIDE the enclosure underneath a thick layer of substrate. There should be no risk of your snake burning itself on the pad if you’re using a thermostat, but if you’re in Europe you can also experiment with the Vivexotic Heat Mat Holder.