Gardeners can grow cacti both indoors and outdoors in a range of pots, including glazed and unglazed clay, plastic and ceramic pots. Because cacti are sensitive to overwatering, the more porous the surface is, the more ideal it is for cacti, making the unglazed clay pot the best option. However, with careful watering and ample drainage holes, gardeners can use any of these pots successfully.
To add drainage to an existing pot, gardeners can use a drill, or a screwdriver and hammer, on clay and ceramic pots to expand existing holes or create new ones. A hot knife or ice pick works on plastic pots. A layer of lava rocks or coarse gravel lining the bottom of the pot can also improve drainage.
Gardeners should select a pot that offers at least 1/4-inch clearance between the main body of the plant and the rim of the pot. Cacti typically have shallower root systems than other container plants and thrive in wide, shallow pots. In general, gardeners should avoid pots that are deeper than necessary, as added soil increases water retention, which can damage sensitive roots and lead to root rot.
If the plant is top heavy with a small root system, gardeners can stabilize the plant without introducing too much soil by placing the cactus’s pot inside a larger pot and pouring gravel into the space between them to brace the smaller pot.