Lighting guidelines will vary depending on whether your succulent is indoors or outside. Provide adequate lighting. Water the plant only after the top inch of soil has dried. Summer can dry out the soil too quickly, leaving your plants without sufficient water. The unique plant can grow in clumps up to 4 inches high and 12 inches wide. They can thrive in a window sill, either facing south or west. A window sill planter such as this white modern one would look amazing with the Bishop’s Cap cactus. The sunburn from exposing this beautiful indoor cactus to direct sunlight will result.