Warm, dry rooms in Colorado homes make the cactus a natural houseplant. Many species of cacti can be grown as houseplants, varying in size, color, shape, and flowering habit. Popular cacti include star cactus, golden barrel, old man, bishop's cap, sunny ears, rat-tail, pin cushion, Turk's cap and ball cactus. Cacti prefer strong sunlight and grow best on southern window sills, or at least an east or west window, which provides direct sun part of the day. Cacti can be placed outdoors during summer months.
Cacti can grow prolifically during the spring and summer, and it's important to water them properly during this growth period. They absorb water rapidly, so be sure to keep the soil slightly moist. Withhold water during the fall and winter when cacti aren't actively growing. Apply only small amounts of water to moisten the soil around the roots, and allow the soil to become dry before you apply additional water. Water every two to three weeks to provide adequate moisture during the no-growth season.
Temperatures during the growth period should be 60 degrees Fahrenheit at night and 70 to 75 degrees Fahrenheit during the day. If possible, reduce the temperature to 45 to 55 degrees Fahrenheit during the no-growth stage. If a room is not available to keep your cacti at 45 to 55 degrees Fahrenheit during the no-growth stage, place your plants near a window where the temperature may be 5 to 10 degrees cooler than the interior of the room.
Feed cacti often with a liquid fertilizer during the growth period. Fertilizers such as five-ten-five or ten-twenty-ten are preferable. Commercially prepared soil mixes that are well-drained provide a good growth environment for cacti. Avoid over-potting cacti, and make sure the roots are well covered to prevent larger plants from toppling over.
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Updated Friday, April 19, 2013