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If you’ve had an old man cactus but it has not produced any flowers, you might be wondering if they bloom, and if so, how do you get them to bloom?
You can get an old man cactus to bloom if you mimic the natural environment and conditions it needs to produce buds. Even so, it may not flower for 10-20 years since that is how long it takes to grow to maturity. Giving it cactus food early in the spring also encourages it to bloom.
If you have an old man cactus that is old enough to produce flowers, there are some other things you can do to encourage it to flower. Most of these come down to basic care and meeting their needs, which is especially important if you are growing it indoors.
Encourage Your Cactus to Bloom by Giving it What it Needs
This is true for any cactus or succulent, if you want it to thrive, or even eventually produce flowers, you should closely mimic the conditions it would have received in its natural environment. The old man cactus, Cephalocereus senilis, is no exception.
This cactus, originating from Mexico, is known for its wispy, white hairs and an almost unkempt appearance. Its unusual appearance is part of why it’s growing in popularity.
You can often find them for sale at garden centers. The plants you buy from a garden center are established and they may already be several years old (the age will vary depending on where they purchase their cactus plants). These cactus plants will not yet be old enough to flower.
You can also find one on Amazon. This is an unrooted cutting of an old man cactus.
Whether they are still young, or mature enough to produce flowers, there are certain conditions that this cactus needs for it to both thrive and to bloom (given time).
Sunlight is Essential
This cactus needs bright sunlight and some direct sun. That means you should keep it in the brightest part of your home. You might even consider using an LED plant light to supplement the light that it needs.
If your summers are warm enough, you may even consider placing them outside for some extra sun. If you do that, be sure to harden the plant gradually before letting it get exposed to too much sun.
You can harden plants by exposing them to a short amount of sun the first day, and increasing the amount a little bit each day until it can handle the sunlight without getting sunburned. I usually start with one hour of sun exposure the first day and then increase the exposure in ½ hour increments each following day.
Water Only When Dry
Water only when the soil is completely dry. When you water it, give it a thorough soaking and let it drain and dry completely before watering it again. This cactus is drought resistant and doesn’t require lots of water, in fact too much water will harm it.
Quick-Draining Soil is Best
The soil should be quick draining. Use a good quality cactus soil mix. You can buy it locally, online, or even make your own. We have a guide here for those who could use instructions on how to make a cactus soil mix.
Use Pots that Allow Evaporation
The ideal pot for this cactus is one that allows for the moisture to evaporate. Clay pots work very well since they allow evaporation through the sides of the pot. This terracotta pot on Amazon is a simple pot that can work very well. This other pot is an alternative style for those that prefer a shallower pot for their cactus plant. Both of them have a drainage hole and come with saucers.
Repot Every Few Years
Your cactus will need to be repotted into a new pot every few years as it outgrows its pot. This is a slow-growing cactus, but it does grow up to 7 inches each year and will become root bound if it’s not repotted. (It usually only gets to about 3-4 feet tall when grown indoors, but gets much much taller in the wild).
Fertilizer Can be Helpful, but Use With Caution
You can fertilize it with a balanced fertilizer during its growing season, which is in the warmer months. Fertilize it once in the spring and optionally, once again later in the summer. Don’t fertilize in the fall and winter months.
Note: Some people recommend that you fertilize it with a half-strength fertilizer since too much fertilizer can cause problems.
Ideal Temperatures Depend on the Season
Old man cactus plants like summer temperatures to be around 65-90 degrees F but need cooler temperatures in the winter. In the winter the temperature should be around 50-60 degrees F.
What About During the Winter?
The old man cactus is a tricky Cactus to get to bloom so if you’re growing it indoors you want to mimic the conditions it would experience in its natural environment as closely as possible. That includes a period of cooler weather and drier conditions in the wintertime. The old man cactus still needs bright light during this time, but the difference in the winter is:
🌵 This cactus needs very little if any water
🌵 You shouldn’t give it any fertilizer
🌵 Only water it when it’s extremely dry. (Usually about 1-2 times in the winter).
🌵 The temperatures should be around 50 to 60°
You shouldn’t keep your old man cactus near heater vents or drafty window. Hot or cold air drafts can damage your cactus.
How Long Does it Take for an Old man cactus to Bloom?
Old man cactus plants may take between 10-20 years to become fully mature enough to bloom. This type of cactus grows very slowly, and they can live to be well over 100 years old. With that in mind, it shouldn’t come as a surprise that it also takes them a long time to become mature enough to produce flowers.
Can an Old Man Cactus Bloom Indoors?
It is rare for an old man cactus to bloom indoors, that is, unless you can successfully mimic the natural conditions it would normally grow in. It needs at least 6-8 hours of full sunlight and a warm temperature of around 65-90 degrees Fahrenheit. It may need to grow to maturity first which can take 10-20 Years.
When it does bloom, old man cactus flowers are often large and reddish pink in color with a distinctive funnel or tubular shape.
Although Old Man cacti rarely bloom when grown indoors, it is well worth giving your plant what it needs to thrive. In the process, you might even get your plant to bloom if the conditions are right.
We have a few related articles about the Old man cactus if you are interested in learning more: How to get an Old Lady Cactus to Bloom and Old Man Cactus vs. Old Lady Cactus
This post was written for cactus-central.com and is not permitted to be used on other sites.