Top Rot on Small Cactus: Cut, Callus, and Prevent Recurrence

Likely Cold Damage

Germany winter, left at window overnight → black/brown mushy top. Classic freeze injury.

Surgery

1. Cut at 45° angle 1–2 inches into firm green tissue.
2. Sterilize knife (alcohol/flame) between cuts.
3. Optional: dust cut with sulfur or copper powder.
4. Callus 1–2 weeks in bright shade.
5. Replant in dry cactus mix; no water 1 week.

Prevention

• Move from windows at night in winter.
• Keep above 50°F.
• Water minimally Nov–Feb.

Angle Cut Helps

Water runs off, reducing re-infection risk.