Living in inhospitable soils that lack the nutrients to sustain other plant life, carnivorous plants gain their nutrition by trapping and feeding on insects. Because most of these plants require a very humid environment, you may need to use a terrarium or other container gardening to grow carnivorous plants in your home. Sundews, Venus fly traps and pitcher plants tend to grow the best in container or terrarium environments.
Substrate and Pool
Before beginning to set up your terrarium, place it in its permanent location. After you've added sand, water and your plants, it will be heavy and difficult to move. Your tank should have about an inch and a half of coarse sand, slightly dampened, on the bottom. You can arrange some small non-alkali stones near the front of the tank to form a small pool and use sphagnum moss to fill in the holes between them. The sphagnum moss will help keep soil mix from falling into the pool through the spaces between stones.
The soil mix you use in your terrarium depends on the species of carnivorous plant you're growing, so consult the care guidelines for your plants. You should place the soil mix around the stones first to help stabilize them, then add a 2- to 3-inch layer of soil mix to the rest of the tank. You can add a layer of sphagnum moss to hide the growing medium and make the terrarium more attractive.
You can plant your carnivorous plants directly into the soil mix. You can also plant specimens that need a different soil type than the other plants in your terrarium in small, well-drained pots and cover the pots with sphagnum moss to hide them. If you are planting in individual containers rather than a terrarium, place a layer of stones in a plastic tray, add water to a level even with the top of the stones, and place your planters in the tray. This helps keep a humid environment around your plants. Give your carnivorous plants a good watering as soon as you've finished planting.
Cover and Lighting
A glass or Plexiglass cover with a vent in the middle allows air movement in the tank and prevents the terrarium walls from fogging up. Place your carnivorous plant terrarium or containers in an area with indirect light. If you're using a terrarium, you can install a hood with two wide-spectrum plant lights and two cool white fluorescent bulbs per 10 to 12 inches of tank width to provide the light your carnivorous plants need.
Salts and minerals present in tap water can damage or kill your carnivorous plants, so distilled water is best. In a planted terrarium, water carefully around the base of the plants and avoid splashing water on the leaves; the humid terrarium environment will not allow the water to dry and can allow diseases to infect your plants. Water the terrarium well and wait a few minutes for the excess water to collect in the stone pool, and then siphon the water back out of the pool. This method of watering will wash mineral and salt buildup out of the soil mix. Keep the soil of container-grown carnivorous plants moist but not soggy.
The roots of carnivorous plants are highly sensitive to minerals. These plants are adapted to growing in soils with very low nutrient concentrations. For this reason, you should not fertilize your carnivorous plants. Instead, feed your plants a few small insects at the frequency recommended by the care instructions for your species of plant.