Temperature
The RHS recommends about 21°C for a general cactus and succulent seed tray.
Growing guide
Sow small cactus seed on a clean, gritty mix, then balance humidity with daily ventilation and filtered light.
The RHS recommends about 21°C for a general cactus and succulent seed tray.
Keep the covered tray in a bright place out of direct sun.
Keep the compost moist but not overly wet, and remove condensation during daily ventilation.
Seedlings can be slow. Some may need up to 12 months before they are large enough to pot on.
Use small pots or trays with a peat-free seed compost amended with horticultural grit or sharp sand. Label the species and sowing date.
Mix very small seed with a little clean sand if needed for more even sowing.
Leave small seed uncovered. Cover larger seed lightly with grit.
Moisten gently, cover with glass or clear plastic, and keep the tray bright but out of direct sun.
Lift the cover and remove condensation daily while maintaining even moisture.
Move seedlings only when they are large enough to handle without damaging their small root systems.
A covered tray can overheat quickly and scorch young seedlings.
New seedlings need steadier moisture than mature cacti, while still requiring air and drainage.
Small cactus seedlings are delicate and may need many months before potting on.
Leave very small seed uncovered and cover larger seed lightly with grit. Follow the packet when it gives species-specific depth.
No. A clear cover helps retain humidity, but the RHS advises daily ventilation and removal of condensation.