One of the most fun aspects of growing any houseplant is propagation: taking cuttings from a plant in order to create new plants. This is no different when it comes to cacti. You can propagate a cactus super easily to give away, sell or expand your own collection.
Find out everything you need to know about how to propagate a cactus and caring for your brand new baby plant!
Propagate a cactus step 1: Take a cutting
The easiest way to propagate a cactus is to take a cutting. This involves removing a part of the plant, which can then form its own root system and continue growing to form a whole new cactus.
All you need to take a cutting is a sharp knife and some alcohol to sterilize the tool. Tongs and gloves might also come in handy if you’re planning on handling one of the more prickly species. And, of course, you need your cactus of choice to multiply! Some of the easiest cacti species to propagate are:
- The genus Opuntia (also known as prickly pear), such as Opuntia microdasys
- Thimble cacti (Mammillaria gracilis)
- Easter lily cacti (Echinopsis subdenudata, from offsets)
- Columnar cacti like the genera Cereus, Pachycereus, Trichocereus
Tip: Don’t have any cacti to take cuttings from? You can start your collection on the cheap by buying unrooted cuttings.
Basically, any species that grows in a clustering fashion is great for cactus propagation, as are segmented ones and elongated ones. Ones that consist of a single round orb are obviously not ideal candidates, since there’s nowhere you can cut without ruining the look.
Select a segment/pad/cluster piece/column that looks healthy and can be removed without making the mother plant lose its appeal. In some cases you can just wiggle the cutting loose, but if not, you can use your sterilized knife to make a clean and easy cut. And there ya have it: a fresh cactus cutting ready to root.
You’ll have to wait for a few days now. Place the cutting in a light location and leave it there; this gives the cut you made time to callous over, which reduces the chances of bacteria or fungus getting into the cutting once it’s planted in soil.
Tip: Some cacti naturally produce offsets (pups) as they grow. You can easily sever these from the mother plant and place them in their own planter. Some will even already have their own root system!
Propagate a cactus step two: Prepare a planter
Once your cutting has dried, it’s time to prepare a pot to plant it in! As with other houseplants, cactus propagation can technically be performed in water, but it’s a pretty uncommon practice since they do so well in soil.
Like all cacti (unless it’s a jungle cactus like the Christmas cactus), your brand new cutting will need excellent drainage to thrive. Cacti roots have not evolved to be used to prolonged periods of moisture. They love a refreshing splash, but after that the soil should quickly dry out again and not be prone to staying wet or humid.
A good cactus soil is not too difficult to recognize: it’ll be gritty and have a relatively low percentage of potting soil, or even none at all. You can make your own mixture for your cutting by combining 1 part potting soil with 1 part perlite and 1 part orchid bark (not overly coarse), but you can also just get a premade cactus soil mixture.
As for planters for your cactus cuttings, you should be all good as long as it offers good drainage. Standard plastic nursery planters are great, although some cactus growers like to offer even more drainage by going for terracotta. This material is porous and as such, allows water to actually evaporate through its walls.
Tip: For more information about planting succulents like cacti, head over to the post on planting succulents indoors.
Propagate a cactus step three: The growing process
If your cactus cutting has callused and you’ve got a soil-filled planter ready to go, let’s start the actual cactus propagation. Got any rooting hormone handy? Dip the base of the cutting in it to stimulate root growth. If you don’t, that’s fine, your cutting should still root naturally.
Pop the cutting into the soil in such a way that it’s stable but not buried too deep. Water a bit and place the planter in a location that’s light but doesn’t get direct sun. Then, prepare to be patient for a good while!
Keep spraying the soil every day or two to stimulate root growth. After 2-3 weeks, give the cutting an ever so slight tug. If you feel any resistance, congrats, your cutting has developed a root system and you should be in the clear.
Once you see the first signs of growth appear, switch to a regular cactus watering schedule and acclimate the plant to a spot with direct sun.
Did you know? In order to save endangered cacti species, some growers have turned to in vitro fertilization (tissue culture) for mass propagation (Giusti et al., 2002). Unfortunately, this is a bit too complicated to do at home.
Bonus: Growing a cactus from seed
If you’re a cactus enthusiast, you’re probably already a pretty patient person, given the fact that these succulents aren’t exactly known for being the quickest growers. Still, unless you have the patience of a saint, you might want to skip trying to grow cacti from seed: it really is a slow process.
If you’re up for the challenge, growing your own cacti can be a fun project and it’s not necessarily too hard, it just takes a long time.
The principle is simple:
- Fill a planter with well-draining cactus soil and thoroughly wet the medium.
- Sprinkle your cactus seeds over the soil, making sure they’re not too close to each other.
- Cover the seeds with a thin layer of additional potting material.
- Place plastic wrap over the planter to create a mini greenhouse and keep moisture in.
- Place the planter in a warm windowsill that gets plenty of light.
- Once you see the first seedlings popping up (it’ll take multiple weeks), remove the plastic wrap. Keep moistening the soil daily, preferably with a spray bottle so you don’t disturb the tiny seedlings.
- When the seedlings start looking like real little cacti over the months, slowly switch to a normal cactus watering schedule.
- The seedlings should be ready to be transplanted to their own planters after about a year or so.
Tip: Make sure you obtain quality seeds. Many sites claim to sell seeds for all sorts of rare and even non-existent cactus species. Planting these will only result in weeds popping up, or nothing at all.
Step four: Caring for your new cactus
You’re now hopefully the proud owner of a brand new cactus. Good job! In case you don’t know how to care for a cactus yet, here are some pointers.
Drainage. As we discussed, this is such an important part of growing cacti. A gritty, airy and well-draining soil as well as a planter with a drainage hole are crucial.
Soils that contain peat are a no-no, as they clump around the roots when they dry and then make it impossible for the cactus to absorb water.
Water. Probably the most common cause of cactus death is overwatering. When it comes to succulents like cacti, remember that they do need regular waterings, especially in summer.
However, they don’t like getting a little bit at a time. When the soil is bone dry, flood it until water runs out of the drainage hole and then leave your cactus alone until it’s completely dry again. You can find more details in the guide on how to water a cactus.
Light. Desert cacti love sun and really want as much light as you can give them. This especially applies indoors.
If you don’t have windowsills that get direct sun, you may want to invest in a simple grow light! You can also move your cacti outdoors during summer, though be sure to acclimate them slowly to the higher light conditions.
- Fertilizing. Cacti are not heavy feeders but the casual grower can feed once a year or so during springtime using a diluted houseplant fertilizer.
Disease & diagnosis. The most common issue you’ll run into with a cactus is rot due to overwatering. This manifests in blackening and softening of the stem. An underwatered cactus will wrinkle and crisp, possibly because there is something wrong with its root system.
Pests are also an issue: white, cottony mealybugs especially like to invade cacti but can be wiped out using a neem oil and water mixture or an insecticide.
If you have any more questions about how to propagate a cactus or want to share your own experiences with cactus propagation, don’t hesitate to leave a comment below! 🌵
Cover photo © Luoxi on Adobe Stock.