Providebright, filtered sun or strong grow lights. Strong, diffused lighting is absolutely necessary to prevent it from fading into a dull, muddy dark green. Protect it from the most intense afternoon summer sun to avoid dry scorch marks.
Follow a classic soak-and-dry approach. Water thoroughly only when the potting mix is dry all the way through and the cactus body yields to a very gentle squeeze. Reduce watering to nearly zero during winter rest.
