Cacti make excellent low-maintenance houseplants, popular among those who forget to water their plants. There are thousands of cactus species that grow in different shapes, sizes, and colours. Cacti are also popular choices due to their slow-growing nature; they are manageable and suit small spaces, but larger species can also make a statement in a bigger space. This is a guide to the basics of taking care of a cactus in your home.
Varieties and Names
1. Golden barrel – Echinocactus grusonii: This round cactus has thick, golden spines.
2. Prickly pear – Opuntia humifusa: This flat-stemmed plant is a classic species, strongly associated with the dessert.
3. Bunny ear – Opuntia microdasys: This is a really popular houseplant with paddle-shaped leaves covered in hundreds of tiny spines.
5. Christmas cactus – Schlumbergera: This is a beautiful winter-flowering cactus with paddle-like leaves that trail over the sides of the pot.
Cacti thrive in as much direct sun as they can get. They typically require 4-6 hours of sunlight a day. However, this isn’t the case for every species; some cactus species prefer bright, indirect light. It’s always safest to check the light requirements of the specific species that you’re growing.
Temperature and humidity
Cacti enjoy hot temperatures with a cooler period in the winter. Generally, the temperatures in your home will suit any type of cactus. Make sure to protect them from any cold draughts and sudden changes in temperature, especially in the winter.
Humidity isn’t too important for most cactus species. Forest cacti and desert cacti have slightly different requirements, with forest cacti preferring more humid environments. Normal household humidity tends to be fine for cacti.
In the warmer months, thoroughly soak the soil of your cactus when it has dried out. Let the excess water drain from the bottom of the pot, making sure the pot is never left to sit in water for too long. In the colder months, you won’t need to water nearly as much – roughly once a month for most cactus species.
Cacti require a lot of drainage and prefer a sandier soil mix. Normal houseplant soil mix, while usable, will not be ideal on its own. You can mix in amendments like perlite, sand, and horticultural grit to make your potting mix better suited to cacti. Alternatively, you could buy a premixed cactus soil.
Fertilising cacti isn’t entirely necessary, but can be done with specific cactus fertilisers. These fertilisers will have more phosphorus than nitrogen, which is better at promoting cactus growth. Only fertilise your plant in the warmer months, diluting the fertiliser according to the instructions on the product.
Pruning and rotation
Cacti rarely need any pruning. The only situations in which you might have to prune a cactus is if you’re removing dead or damaged material or using the cuttings for propagation.
Turn your cactus regularly to make sure each side of the plant is receiving the same amount of light. This is especially important in the spring and summer; rotate it roughly once every two weeks.
Repotting cacti is risky business. Luckily, they grow slowly and won’t need repotting that often. However, once your cactus gets rootbound you’ll need to move it up a pot size or two.
When repotting a cactus, always wear gardening gloves. I recommend having a pair of tweezers handy just in case you get a spike in your skin. Another tip for smaller cacti is to use chopsticks to lift it from its pot. Just make sure you don’t apply too much pressure and damage the plant.
Pests and diseases
Keep an eye out for any common houseplant pests like spider mites, aphids, and mealybugs. Also, be vigilant about overwatering to prevent root rot. Your plant might be suffering from rot if there are dark, soft areas on the stems. If you notice this, examine the roots and remove any damaged material before treating the plant with a hydrogen peroxide solution.