Sun: These cacti prefer lots of sun, at least five hours of direct sun daily. Indoors a south facing window is ideal. Outdoors, place them in a spot where they will get plenty of sun exposure. If you are growing this plant outdoors be sure to provide it with light shade to protect it from intense, peak afternoon sun.
Water: prefer to stay on the dry side. In the summer water them only when the soil has dried out entirely. Always err 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 it’s safe to cut back on watering entirely. This will encourage flowering during the spring!