Stenocactus Multicostatus

Botanical Name — Stenocactus multicostatus

Common Name — Brain Cactus

Plant Family — Cactaceae

Background

Stenocactus multicostatus, known as the Brain Cactus for its rippling, wavy ribs, is a fascinating plant native to Mexico. Large spikes emerge from areoles along the densely pleated ribs. As the plant matures, it readily produces limbs and pups that can be easily propagated. Keep an eye out for striped purple and white flowers, which emerge during summer.

Growth Requirements

Sun

These cacti prefer lots of sun, at least five hours of direct sun daily.
Indoors, a south or west facing window is ideal. Outdoors, give them a place where they will get consistent sunlight and some light shade.

Temperature/ Humidity

Temperatures above 70 ºF in the summer are preferred. But since these plants are native to high elevations, they are also accustomed to seasonal cool weather. During the winter they prefer cooler temperatures, between 50 and 60 ºF.
If grown outdoors, move them to a sunny windowsill inside in regions where temperatures regularly drop below 50 ºF.

Water

Stenocactus multicostatus prefer to stay on the dry side. In the summer water them only when the soil has dried out entirely. Always error on the side of underwatering. They are built to withstand drought, and overwatering is one of the quickest ways to kill them.
During the winter, water very infrequently. Maybe even once a month or month and a half. It’s safe to cut back on watering entirely. This will encourage flowering during the spring!

Soil/Roots

Stenocactus multicostatus are native to rocky slopes and a desert climate. They prefer a gritty, well-draining soil mix. A cactus mix works fine. You can amend it with sand or fine pumice up to 50% to improve grittiness and drainage.

Flowering

Stenocactus multicostatus will produce clusters of purple and white striped flowers about 1 inch wide, usually between spring and summer. Exposing your cactus to drought while it is dormant during the winter will encourage blooming during the growing season.

Fertilization

Stenocactus multicostatus appreciate fertilization during the active growing season. Apply a balanced fertilizer diluted at half strength, once a month. Never fertilize in winter.

Propagation

Stenocactus multicostatus are typically propagated by separating offsets, limbs, and pups from the mother plant. Snip the pups away using sterilized clips of a knife, or, when repotting the plant, remove the roots and separate the pups with some roots attached. For pups removed by cutting, allow to callous before planting directly in the soil mixture mentioned above.

Health

Diseases

Stenocactus multicostatus are not especially susceptible to pests or diseases. Keep an eye out for common pests such as aphids, mealy bugs, and scale.
Root rot can be a common issue in the instance of overwatering.

Maintenance (pruning, legginess, repotting)

Stenocactus multicostatus are very low maintenance. They prefer to be pot bound. Repot them once every two to three years. Early spring is the best time to repot, when they are just waking from their dormancy.

Toxicity