Q: About humidity and air circulation.

• Drosera prolifera
• Drosera binata
• Pinguicula 'Pirouette'
• Ibicella lutea

A: Most carnivorous plants require highly humid conditions. A terrarium provides the 50-90% humidity most carnivorous plants desire. But since most plants desire some air circulation, I do not recommend you seal the terrarium. Air circulation seems to be particularly important for Pinguicula native to the U.S., while Nepenthes do very well in sealed terraria.

Some people do not use terraria, but instead put their plants on a plate or tray filled with water or pebbles and water. This may help the humidity a tiny bit, but I do not think it is very effective. The best way to increase the humidity where the leaves are (which is where it counts) is to use a bit of clear plastic as a tent over the plant. If you live in a humid area, this is probably not required. But if you live in dry areas, increasing humidity may be an important consideration.

If nothing else, consider trying a bottle terrarium as a way of increasing the humidity around your little plant.

Page citations: Rice, B.A. 2006a; personal observation.