Decided to boost the heat in my greenhouse shelf terrarium by adding a seedling heat mat underneath the humidity trays. The cooler December weather has really slowed down my lowland Nepenthes! A few of my plants were also unhappy about the higher light intensity after adding the Carnivero Florawave light, so I wanted to remove the LED shoplight and make it the Florwave the sole light source, which would make the terrarium even colder.
I am using an iPower 20" x 20: seedling heat mat connected to an iPower thermostat set to 85F. I taped the thermostat probe to the center of the back wall.
I duct-taped two 10" x 20" seedling trays together so that no water would escape down the middle, then filled them with about an inch deep of black lava rock to increase the surface area for the warmed water to evaporate from. Hopefully this boosts the relative humidity in the terrarium! I then overlaid the trays with egg crate light diffuser to provide a level surface for my plants. I decided to do away with the multiple shelves and just have a single level to maximize space in the terrarium (a constant problem!)
Temperature and humidity measured by my SensorPush look spot on! Loving the increase in daytime temperature. I plugged the heat mat into my timer so that it only turns on during the daytime, that way we still get modest night time drops. The humidity is interesting - seems to be more stable, although I am curious why night time humidity does not stay close to 100% like it did prior to adding the heat mat.
It's been about two weeks since adding the heat mat and removing the LED shoplight. The plants are LOVING it! My lowlanders have definitely appreciated the boost in warmth and are rewarding me with noticeably faster growth. The heat mat seems to turn on for about 4-5 hours before shutting off.