Lyn is a horticulturist and YouTuber with over 35 years of experience growing succulents and cacti.
Why Won't My Cactus Flower?
I'm going to share five tips for how you can get your cactus to flower. Now, I'm talking about the desert types of cacti. As for epiphytic rainforest cacti, well that's another article entirely. This article is about desert cacti.
It is worth mentioning upfront that some desert cacti have to be very mature before they will flower. If you have some of the Cereus-type cacti, they may never flower in your home, or at least not until they get very large.
5 Tips for Flowering Indoor Cacti
- Provide Plenty of Sunshine
- Be Sure to Overwinter
- Avoid Over-Potting
- Use High Potassium Fertilizer
- Wait for Full Maturity
1. Provide Plenty of Sunshine
The first tip is all about sunshine! Having enough sunlight is absolutely paramount because a cactus will not flower in a dark corner or in the middle of a living room. It has to have plenty of sunshine.
If you have a sunny window that's ideal. Ideally a south-facing window. The desert cacti like to have as much sun as possible, so that is your number one priority. If you don't have a sunny position and you only have a north-facing window—a window that doesn't get much sun—then I suggest installing an LED plant grow light to help encourage blooming. LED grow lights can replace natural sunshine to provide the full photosynthesis that these plants need to produce blooms.
2. Be Sure to Overwinter
The second tip is overwintering. Desert cacti need a cool and dry rest period over the winter to produce their flowers. If they're kept in a heated home during the winter and still watered as normal, they will continue growing which will prevent them from blooming the following spring. So a cool, dry rest period is a necessity. Do not give them water during the winter. That way, these plants can fully rest through the season to encourage blooming.
3. Avoid Over-Potting
The third tip is not to overpot. It's very tempting to plant a cactus in a great big pot. All this will do is encourage the plant to produce more roots and growth rather than flowers. If a cactus is slightly root bound—just very slightly—it will encourage more flowering. So, use the right size pot for the cactus and don't overpot it.
4. Use High Potassium Fertilizer
The fourth tip is to fertilize. You might laugh when I tell you what I like to use—tomato feed is absolutely brilliant to encourage more flowering on cacti. That's because it's high in potassium. If you have a feed that is high in nitrogen it just encourages more growth and not necessarily as many flowers. So a high potassium fertilizer is an excellent tip to encourage more blooming.
I like to dilute the fertilizer to half the strength that is recommended to use for tomatoes. It is an excellent way to get more blooms on your cacti from spring all the way through summer. Just use the fertilizer with every third watering.
5. Wait for Full Maturity
Lastly, we have tip number five. As I mentioned at the very beginning, there are some cacti that may never flower in cultivation. If you have them indoors, a lot of the tall-growing Cereus cacti just won't flower.
For example, if you have a saguaro cactus in your living room, it could be getting plenty of sunshine and growing really well. But it will never flower indoors until it reaches probably about twenty feet in height. The same is true with some of the other tall cacti as well, and even some of the golden barrel cacti have to be very large and very mature before they will flower.
So if you have a cactus and you're doing everything right—it's in a sunny window, you're fertilizing it, you haven't over potted it—and it still doesn't flower, maybe it's because it's still a bit too young. Maybe it will flower eventually, in many, many years.
I hope found the tips useful. Now you know what you can do to get your cactus to flower. If you would like more information on growing cacti, check out some of my other articles below.
More About Growing Cacti
- How to Repot a Cactus Without Getting Hurt
Step-by-step instructions on how to repot and safely handle cacti in your garden.
- Do Cacti and Succulents Need Direct Sunlight?
Some cacti and succulents need plenty of sun, but some can fare quite well in indirect light. Find the best option for you and your home.
© 2021 Lyn Kimberley