How to Make a Cactus Terrarium

Choose your container. You will need to use a container with a wide, open top to make a terrarium suitable for cactus. An empty aquarium makes an ideal container for your first cactus terrarium.

Clean the container thoroughly. Wash your container with a mixture of one part bleach to ten parts water. Rinse and dry it thoroughly to prevent fungi and algae from growing in the terrarium and killing your houseplants.

Prepare for planting. Line the bottom of your cactus terrarium with two inches of gravel covered by 1/4 inch of horticultural charcoal to keep the terrarium from developing odors. The top layer should be four inches special soil, a mix of one part sand to two parts potting soil.

Purchase small cactus plants for your terrarium. Some types to consider include bunny ears cactus, sea urchin cactus, hen and chicks, goat's horn cactus and pygmy cactus.

Plant your terrarium. Dig hollow holes in the soil of your terrarium and transfer your cacti into these holes. Use a pair of tongs to move your cactus plants into their new home.

Care for your cactus terrarium. Place it in an area with indirect natural light and water only once a month at the most. As with any houseplant, test the soil for dryness before watering.