Winter Dormancy on rebutia
What's Happening
Basements and enclosed storage areas during winter create the 'perfect storm' for fungal infection: cold temperatures (slowing plant metabolism), high ambient humidity (condensation on surfaces), poor air circulation, and darkness. Soil naturally contains dormant fungal spores that activate in these conditions. Condensation from ambient humidity enters through minor wounds or scratches on cactus skin, leading to slow-healing infections that spread during dormancy.
How to Fix It
- 1
Inspect every cactus for wounds, cuts, or damaged areas before winter storage
- 2
Treat any wounds with sulfur powder, cinnamon, or fungicide to create protective barrier
- 3
Choose overwintering spot with: temperatures 45-55°F, humidity below 40%, and air circulation (fan if needed)
- 4
Place silica gel packs or dehumidifier in storage area to prevent condensation
- 5
Space plants apart - never stack or crowd - air must flow around each specimen
- 6
Consider bare-root storage for high-value specimens in problematic environments
- 7
Monthly inspection: Check for soft spots, discoloration, or fungal growth during dormancy period
How to Prevent It
Choose overwintering locations carefully: cool (45-55°F/7-13°C), bone-dry (humidity below 40%), and well-ventilated with air circulation. Avoid basements with concrete floors that wick moisture. Use silica gel packs or dehumidifiers to control humidity. Inspect all cacti for wounds before storage and treat with sulfur powder or cinnamon on cut surfaces.