Bishop’s Cap

full sun (6 or more hours of sun hitting the leaves per day. South-facing window, no obstructions. Under grow lights, keep them 4-8 inches away for 12-14 hours) to bright indirect light (3-6 feet from a south or west window, or right next to an east window. Under a grow light, 6-10 inches away works well); 6-8 hours of sun daily is ideal. A south-facing window works well indoors. Protect from intense afternoon sun during summer heat.

Prefers low humidity; high moisture leads to fungal rot. Good air circulation is more important than any specific humidity target.

Fast-draining cactus mix: 70-80% inorganic material (pumice, perlite, coarse sand, lava rock) with 20-30% organic matter. Never use moisture-retaining potting mixes.

Overwatering and root rot are the main killers. Mealybugs and scale insects appear if kept too warm in winter. Avoid touching the white scales -- oils from your skin rub them off permanently and leave the cactus vulnerable to sunburn.