I have a small collection of cacti that I keep as houseplants and they never flower. Any ideas why?
Answer: Cacti are striking, exotic plants that fill homes and gardens with an abundance of eccentric splendor. If your indoor cacti are not blooming, it is probably due to an issue with lighting, temperature, soil and/or water. Also, some cacti species can take up to 50 years before they are mature enough to blossom! When you purchase a cactus from a garden center or nursery, it is a good idea to select one that is in bloom, so you know it is old enough to do so.
Proper maintenance will vary depending on the type of cacti you are growing. There are two main types of cacti: desert and jungle/forest cacti. The difference between the two is relatively simple: desert types originate in desert regions, and jungle/forest cacti are native to tropical areas. Here are general growing requirements for each type, though various species may need additional care.
• Soil/fertilizer: Desert cacti are successful when planted in a well-drained potting mix specifically used for growing cacti. If you do not have access to cacti potting mix, make sure to use soil that has ingredients such as perlite, sand and Supersoil mixed into it. Apply a cacti-specific fertilizer only during the growing season. Make sure not to keep feeding fertilizer once the season is over, because the cacti need to begin preparing for dormancy. The dormant period—usually during the cold, dry months of winter—is essential to healthy, flourishing plants.
• Water: One of the most common mistakes cacti growers make is overwatering. Generally you should water only when the top inch of soil feels dry to the touch. During a cactus’s dormant period, you can cut back to only once a month—or just as the cactus begins to shrivel.
• Lighting: Desert cacti thrive when grown in very sunny locations. They need strong, constant light to prosper. Make sure to place them in a south- or west-facing window, supplementing with fluorescent lights when necessary. Keep them in a location with consistent temperatures between 55 and 80˚F. During their winter dormancy, make sure to keep them in a cooler (yet still bright) area—50 to 55˚F if possible.
• Soil/fertilizer: Most jungle/forest cacti will successfully grow in average well-drained potting soil. For better chances of success, you can add perlite to the soil for faster drainage. You can use a general fertilizer during the growing season; however make sure not to feed the cacti during the dormant period.
• Water: Typically water jungle/forest cacti can be watered once per week. During winter/dormant months, water only when soil is dry to the touch. If plant begins to shrivel, you may be watering too little or too often. Test soil by touching it to see what adjustment is needed.
• Lighting: Jungle/forest cacti do not need as much sun as desert varieties and need some periods of shade to flourish. Keep them in a bright location, but make sure they have some time each day when the sun’s rays aren’t striking them.
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