Expert: Christopher Littrell - 3/6/2008

Question
Two questions:

1.  I thought about creating a bog out of my terrarium.  Basically, I would fill the tank with a certain amount of peat/perlite, put the pitchers into the dirt (once they grew, of course.  I'm in the seedling stage), and keep dumping water into it to keep things wet.  Is that the basic thing to do?  And how deep should the dirt be?

2.  I have other CPs in there that may not survive a bog.  Can I put the pots on stands to keep them elevated above the bog surface, or will I risk fungus or something?

Answer
Hello Talisha,

In general, it is best to grow carnivorous plants of most any species as open pot plants. Only a few of the more demanding Nepenthes require humidity and temperature control that terrariums can provide. North American Sarracenias, Darlingtonia, Venus Flytraps, Pinguiculas, most Drosera, most Nepenthes, and terrestrial Utricularias really do not need extra humidity or temperature control and do best out of a terrarium in normal room temperatures and in whatever humidity you happen to have them adapted to... so long as the humidity is above 15 percent. I grow all my plants on shelves or tables near windows and with added florescent lights to make up for day length and intensity where needed. All are open pot and most are sitting in water trays... except for my two Nepenthes that would not like standing water under their roots.

Terrariums would tend to increase the risk of souring soil, fungus, bacterial infection, root rot from standing water, and keeps the plants from getting as much natural light or air flow... the two main things that decrease fungal attack.

If you really want to try a terrarium, it can work, but you will have to add small fans and place a layer of pebbles in the bottom to add a couple inches of drainage, only adding water as you notice the soil moisture evaporating after several days. The 50/50 peat perlite would need to be at least 4-6 inches deep, the deeper the better though. In total, with the moss and perlite on top of a layer of drainage material you would have about 8 or so inches of rooting space, so would require a tall terrarium. The greatest number of carnivorous plant losses I have had are mostly from plants grown in terrariums just as fair warning. I have thus far had no losses with my present open pot plants at all.. most are reproducing like mad.

Good plants for terrariums would be small tropical sundews like pygmy sundews, Drosera spatulata, Drosera adelae, and Drosera capensis, though really all those can be grown open pot easily, the pygmies grown in warmer areas as they like slightly higher than room temperature living conditions of around 80F or so. Other plants good for terrariums would be N. rajah and other more difficult highland and ultra-highland Nepenthes.

Good luck with your terrarium,

Christopher