Moon Cactus
Gymnocalycium mihanovichii
The Moon Cactus is a grafted succulent with a neon-colored globe on top of a green rootstock, usually Hylocereus. The colorful scion lacks chlorophyll, so it depends on the green base for photosynthesis. The two-toned look works well in small pots and bright indoor spots.
Light
Bright Indirect
Water
Low
Difficulty
Easy
Humidity
Low
Pet Friendly
The Moon Cactus is non-toxic to cats and dogs, though its sharp spines can cause physical injury if the plant is handled or consumed.
Care Notes
Light
Place in bright, indirect light. Intense midday sun easily scorches the colorful top.
Water
Use soak-and-dry watering. Let the mix dry completely, then water thoroughly. In winter, water about every 4 to 6 weeks. Always empty the saucer.
Soil
Use a gritty cactus mix with perlite, pumice, or sand in a pot with drainage holes. Wet soil is the fastest way to lose the rootstock.
Humidity and Temperature
Keep temperatures between 60°F and 85°F. Protect from frost and cold drafts. Low humidity is fine. The grafted top and rootstock grow at different rates, so the graft may weaken after a few years and need re-grafting.
Common Issues
A soft or shriveling base usually means overwatering or root rot. A pale, stretched top often means too little light.
In-Depth Care & Growth
Feeding & Soil
Fertilizer
Balanced liquid cactus fertilizer
Soil
Gritty, well-draining cactus potting mix
Physical Attributes
Mature Size
4-6 inches tall
Growth Rate
Slow
Propagation
Grafting offsets (pups) onto a new rootstock
Common Varieties
Hibotan (Red)
A small globular form with a neon-red body and clear vertical ribs.
Yellow
A neon-yellow globe with sharp horizontal ridges and small pale spines.
Orange
A neon-orange globe with prominent vertical ribs and horizontal banding.
Pink
A neon pink ribbed globe with clear horizontal banding.
Purple
A violet or burgundy ribbed globe with horizontal banding and a segmented geometric shape.