How to Grow a Cactus in a Terrarium

Every plant enthusiast has at one point wanted to move a bit of the outdoors inside. Whether your plant preference leans toward foliage plants, exotic plants, carnivorous plants or even cacti, you can grow them in a tightly controlled environment using a terrarium. By strict definition, a terrarium is a closed container, but many open-topped terrariums are in vogue today. These are the terrariums best suited to growing one or more cacti.

Open-topped clear container, sized appropriately
Pebbles
Activated charcoal
Sphagnum Moss
Sterilized potting soil
Sterilized sand
Cactus
Cool white florescent lighting
Hygrometer, optional

Instructions

- 1
  Place a layer of pebbles at least 1/2-inch deep on the bottom of the terrarium. Layer activated charcoal in a second layer 1/2-inch deep above the pebbles. Top these layers with sphagnum moss to prevent the soil layer from penetrating this drainage layer.
- 2
  Mix one part potting soil to one part sand. Measure the depth of the cactus's root ball and fill the terrarium at least 1/2-inch higher than this figure. Plant the cactus so the terrarium's soil is even with the crown of the plant.
- 3
  Water the terrarium until it is just moist. Grab a small handful of the moistened soil and squeeze it, if it still falls apart, you've watered it enough. Place a hygrometer in one corner of the container and check it regularly -- proper humidity for cacti is between 10 and 30 percent. Withhold water until the humidity inside the terrarium is extremely low, only water a very little bit at a time. Hang the cool florescent light just above the terrarium and leave it on for at least 12 hours each day.

What Are the Basic Needs of the Saguaro Cactus?

How to Grow a Cactus in Fluorescent Lighting

Growing Cactus