Otherwise, this plant is pretty hardy and doesn’t have any serious issues with pests or diseases. Plan to water and feed your cactus more regularly in the spring through early fall than in the late fall and winter months. And repot container plants as needed once they’ve outgrown their containers. When planted outdoors or placed in an outdoor container garden, position your brain cactus in a spot that has some protection from strong winds, which can be damaging to the plant.
Light
Brain cacti thrive in full sun, meaning at least six hours of direct sunlight on most days. They can tolerate a bit of shade, but they won’t grow to their fullest potential and flower at their best in lower-light conditions. Indoors, place your brain cactus by your brightest window. A west-facing window is typically ideal.
Soil
These cacti prefer sandy and rocky soil that has sharp drainage, just like melon cacti. But they can survive in a variety of soil types as long as there’s good drainage. A slightly acidic to slightly alkaline soil pH is fine. For container plants, a fast-draining potting mix made specifically for cacti and succulents is best.
Water
To prevent root rot, it’s best to allow the soil to dry out almost completely in between waterings of your brain cactus. The plant has good drought tolerance. In the spring and summer, watering roughly every two weeks should suffice. Once the weather starts to turn cold in the fall, reduce watering to every three weeks to a month, and carry on this way through the winter. The cactus is not actively growing during the colder months, so it doesn’t need as much water as it does during the warmer parts of the year. It’s better to water deeply and then wait for the soil to dry out versus watering in little bits more regularly. The latter method makes overwatering more likely. Always empty the drip tray on a container plant after you’ve watered.
Temperature and Humidity
This cactus thrives in warm, dry conditions. It can tolerate temperatures down to 20 degrees Fahrenheit, though prolonged exposure to frost and freezing temperatures can eventually kill it. Ideally, it prefers to be in temperatures of 50 degrees Fahrenheit and above. The cactus is fine in low to moderate humidity levels. But high humidity can cause the soil to retain too much moisture, leading to root rot. So in humid conditions, careful watering and excellent soil drainage are essential.
Fertilizer
The brain cactus is not a heavy feeder, but it does appreciate some fertilizer when it’s actively growing. During the spring and summer months, use a liquid fertilizer on your plant that is made specifically for cacti and succulents. There’s no need to fertilize in the fall and winter months when the cactus goes dormant.
Propagating the Brain Cactus
Brain cacti are easy to propagate from seed. Simply press the seeds into a seed starter mix in a shallow tray. Put them in a warm spot, and keep the soil just barely moist. Germination should take a couple weeks.
Potting and Repotting the Brain Cactus
The ideal pot for a brain cactus should have ample drainage holes. An unglazed pot is helpful because it also will allow excess soil moisture to escape through its walls. Plus, the cactus has shallow roots, so it doesn’t need a container with a lot of depth. It also doesn’t mind being a little cramped in its container. But once you see roots growing out of the pot and the cactus has become top-heavy, it’s time for repotting. Because the cactus is a slow grower, it likely will only need repotting every two to three years or so. Gently remove it from its old pot, and place it in just one container size up with fresh potting mix. Wait about a week before watering, so the roots can get adjusted.
Brain Cactus Varieties
There are several other species in the Stenocactus genus that also use the common name of brain cactus, including:
Stenocactus crispatus: This species features dark green ribbing, long spines, and pale violet flowers.Stenocactus phyllacanthus: This plant produces small yellow flowers and has stiff, tan spines.Stenocactus coptonogonus: This species has straight (not wavy) ribbing and blooms with white flowers that have lavender stripes.
