Reasons a Cactus Won’t Bloom
The type of cactus you grow may actually be unable to produce flowers for many decades. 50 to 100 years is not uncommon for cactus bloom times on certain varieties. If you desire ready flowering indoor cactus, choose from the following types:
Mammillaria
Gymnocalycium
Parodia
Notocactus
How to Get a Cactus to Bloom
When keeping cactus indoors during winter, try to locate them in the coolest spot. While they likely won’t survive outdoors below 20 degrees F. (-6 C.), they do need a chilling period to bloom. Also, keep in mind, if they are outside in temps this cold, they must stay completely dry. Indoor cactus doesn’t need water during the winter either. Withhold all water during their period of dormancy, waiting for signs of growth to resume watering. This encourages flowering. At this time, if you’ve not already positioned your cacti in a full sun position, this is a great way to get blooms. Full morning sun is best, with the exception of jungle/forest cacti that can take dappled sun or just bright light. Cacti, as with other plants, should be gradually acclimated to the sun so they don’t get a sunburn. Begin with an hour or two and increase weekly for desert cactus, until your plant is getting at least six hours of sun daily. An indoor lighting system may work if actual sunshine is not available. However, if you can move the plant outdoors when temperatures warm, do so. When you start watering again, you may also lightly feed with a high phosphorus fertilizer. Use it at half strength, watering first. If you have fertilizer already on hand, check the fertilizer ratio and make sure the middle number is highest. Nitrogen fertilizer (first number) is not good for cactus and succulents, as it creates weak and spindly growth, so avoid this when possible. High phosphorus fertilizer is sometimes labeled as “Bloom Buster.” Following this regime, when do cacti flower? Late spring or summer for some, while others may not blossom until winter. Remember, don’t expect blooms until your plant is mature. Google the type of cactus you have to learn more about its age at first bloom. Now that you’ve learned how to get a cactus to bloom, you can proceed with getting flowers on those mature plants that have not yet flowered. Enjoy the show!
