Why isn’t my cactus blooming?
I’ll give you five tips on how to make your cactus bloom. Now I’m talking about the desert cactus species. As for epiphytic rainforest cacti, that’s a whole different article. This article is about desert cacti.
It’s worth noting that some desert cacti need to be very mature before they bloom. If you have some Cereus-type cacti, they may never bloom in your home, or at least not until they get very large.
1. Provide plenty of sunshine
The first tip is all about sunshine! Sufficient sunlight is absolutely important because a cactus does not bloom in a dark corner or in the middle of the living room. There must be lots of sunshine.
If you have a sunny window, that’s ideal. Ideally a south window. Desert cacti want as much sun as possible, so this is their top priority. If you don’t have a sunny location and only have a north-facing window – a window that doesn’t get much sun – then I recommend installing an LED grow light to encourage flowering. LED grow lights can replace natural sunlight to allow for the full photosynthesis these plants need to form flowers.
2. Be sure to overwinter
The second tip is wintering. Desert cacti require a cool, dry dormant period in winter to produce their flowers. If they are left in a heated house over the winter and continue to be watered as usual, they will continue to grow and may not bloom the following spring. Therefore, a cool, dry rest period is a must. Don’t give them water in winter. This allows these plants to have complete rest throughout the season to encourage flowering.
3. Avoid overpotting
The third tip is not to pot too much. It is very tempting to plant a cactus in a large pot. This simply encourages the plant to produce more roots and more growth than flowers. When a cactus is lightly root bound – just very slightly – this encourages more vigorous blooming. Therefore, use the right size pot for the cactus and do not overpot it.
4. Use potassium-rich fertilizer
The fourth tip is fertilizing. You might laugh when I tell you what I like to use – tomato food is absolutely excellent for encouraging cactus blooms. This is because it contains a lot of potassium. If you have a high nitrogen feed it will only encourage more growth and not necessarily as many flowers. Therefore, a potassium-rich fertilizer is an excellent tip to encourage stronger blooms.
I like to dilute the fertilizer to half the strength recommended for tomatoes. This is an excellent way to add more blooms to your cacti from spring through summer. Simply use the fertilizer every third watering.
5. Wait for full ripeness
Finally, tip number five. As I mentioned at the beginning, there are some cacti that may never bloom when grown. If you have them indoors, many of the tall growing Cereus cacti simply won’t bloom.