Is a Venus Flytrap terrarium a good idea? I’ll give you the short answer: NO.
Still thinking about it? Here’s a longer answer: HELL NO.
Now that that’s out of my system, I’ll explain why.
Issue #1: Humidity
Contrary to popular belief, Venus flytraps do not thrive in environments with high humidity. Some wetness is fine, but we must consider their original habitat and compare it to the environment we want to create in a terrarium. The flytrap’s native environment consists of open, sunny grasslands and wet savannas. In other words, open space with full sunlight and sandy, peaty soils. A glass enclosure is not going to give the flytrap’s root system enough aeration to survive. It will most likely succumb to root rot and die. Even a terrarium with an open top is going to resemble too much of a jungle environment. It will work fine for some tropical carnivores, but not Venus Flytraps, Sarracenia, and other temperate plants.
Issue #2: Drainage
Drainage in a terrarium is actually an issue with most carnivorous plants due to how they evolved. Most carnivores thrive in soil that is very poor in nutrients and minerals. Their nutrients come from their food. Minerals will build in the soil over time, and if not regularly flushed out with water, will eventually burn their roots and kill them. Terrariums most often do not have drainage holes, so there is nowhere for minerals to be flushed out when watered. This leaves ample opportunity for mineral buildup and shortening the lifespan of a Venus flytrap terrarium.
Issue #3: Heat
Remember when kids would burn up ants and other bugs by holding a magnifying glass over them under direct sunlight? The same thing can happen to a Venus flytrap in a terrarium. It’s true flytraps love all the direct sunlight they can get, but the glass or plastic walls of a terrarium is going to amplify that heat to deadly amounts. I remember one summer here in California, we had several days of over 100 F (38+ C) temperatures. The hottest it got was around 110 F (43 C). My traps (always outside) survived, but had some burn damage. In my experience, they can tolerate around 100 F for a short period as long as they’re watered enough. But even if a Venus flytrapterrarium is indoors, the temperature inside it can go way up in direct sunlight.
Issue #4: Dormancy
If you read my post on different types of carnivorous plants, you know that a winter dormancy is essential to a Venus flytrap’s longevity. A terrarium is certainly not going to allow for that. Sure, you can shorten the photo period to simulate a seasonal change, but this is basically a two-part issue with heat. In a terrarium, you cannot lower the temperature enough to trigger a winter dormancy. Ideally, you need temperatures between 50 – 32F (10 – 0 C). This means you would have to abandon the terrarium entirely for about four months out of the year, which defeats the whole purpose of having one.
Issue #5: Different needs from other plants
This is the issue that culminates the first four issues mentioned. While some carnivores will fare excellently in terrariums, these environments will just not suit the needs of Venus flytraps. Many enthusiastic new growers will want a diverse collection of carnivores all in one location to admire. They’ll put Venus flytraps in a terrarium with butterworts, tropical pitcher plants, and throw in some sundews for good measure. While this will look pretty and exotic for a few weeks or months, all of those plants have very different soil, light, and humidity needs. Throwing them all in one tank will simply not work for the long term.
I hope this post clarified on the reasons why a Venus flytrap terrarium is not the best idea. But don’t worry if you had your heart set on carnivorous plant terrarium! In Peter D’Amato’s The Savage Garden, there is a whole section on terrariums and what types are best for certain plants. I wrote about terrarium-friendly plants briefly in this post. Personally, I’m planning on making a greenhouse-style terrarium for tropical plants as soon as I get a tank and enough space in my house!
Thanks for reading! Feel free to leave a comment if you have any further questions!