Field guide 06 · Seasonal
The cold windowsill
Dormancy is not death. How to hold a collection through four months of low light, cold glass and central heating.
Winter kills more indoor succulents than any other season, and almost always through the same route: a cold window, a wet pot, and a plant that was watered on schedule. The plant is not growing. It does not need what it needed in June.
What dormancy looks like
Growth stops. Lower leaves may yellow and drop. Rosettes close slightly and colour deepens — the reds and purples people pay for in autumn are a stress response to cold and bright light, not a sign of trouble. A lithops will wrinkle and absorb an outer pair of leaves; that is the process, not a cry for water.
The three winter rules
Move plants off the glass: a windowsill can sit 5 °C colder than the room, and cold wet roots rot first. Reduce water by half or more, and skip entirely in any week the mix has not dried. Stop feeding from October to March.
| Temperature | Water | Position |
|---|---|---|
| Above 18 °C, bright | Every 3–4 weeks | South window, away from glass |
| 12–18 °C | Every 5–6 weeks | Brightest sill available |
| Below 10 °C | Once, in December, if dry | Cool and dry is fine; wet is not |
Ventilation beats heat
Still, warm, humid air in a closed room is the condition that grows mould on a rosette. A ten-minute exchange of air on a mild morning does more good than raising the thermostat. If you run a dehumidifier in the room, the plants will thank you.
