Oregonian here with a growing cactus collection in a greenhouse. Some of my cacti flower regularly, mostly Mammillaria. I’ve always wondered when a cactus appears to be producing a flower, is there anything I should be doing to promote the flower’s growth? Take it outside, more light, less light, feed it, water it, don’t touch it, don’t move it…. you get the idea. I don’t get too many flowers, and I try to acknowledge their dormancy period during the winter to help the spring/summer flowering, but still have mixed results. Fortunately I have what appears to be an Echinopsis flower coming and I don’t want to screw it up?
There are 2 different issues here:
1. How to get more flowers. We use fish bone meal as a bloom food in late March or early April (now is not too late.) Using a regular cactus fertilizer is also a good idea in the spring.
2. Once the bud is already there, nothing needs to be done to promote its growth. However, there are things you can avoid doing to prevent it from aborting. It’s best not to replant any plant that has started blooming, as the shock can cause the blooms to abort. It’s also best not to change it’s environment too radically, like bringing it from inside to full sun outside. To keep blooms longer, avoid high heat.
Hope that helps
And as a bonus, enjoy a blooming cactus:
Notice all those flower buds all over the tiny cactus? That’s another secret to getting cactus blooms: Pick a cactus that produces lots of flowers, like a rebutia.