Overwintering guide
How to overwinter azolla pinnata
Winter watering
Water only occasionally — enough that the rootball never dries out completely, no more. No feeding until spring growth begins.
The mistake that kills azolla pinnata in winter
Bringing azolla pinnata into a warm living room. Too much winter warmth forces weak, pale growth that collapses when it goes back outside — cool and bright beats warm and dim.
More azolla pinnata care
Overwintering azolla pinnata — FAQ
Does azolla pinnata need to come indoors for winter?
Azolla pinnata is hardy to roughly USDA zone 9 — winter lows around -7°C. That means it takes cool conditions but not a real freeze. Azolla pinnata will take cool conditions but not a hard freeze, so the aim is a frost-free winter rather than a warm one. An unheated greenhouse, porch, conservatory or bright garage all work well. Keep it cool, bright and on the dry side, and it will hold steady until growth restarts in spring.
When should I move azolla pinnata for winter?
Move under cover before the first hard frost; back outside after the last spring frost.
How often should I water azolla pinnata in winter?
Water only occasionally — enough that the rootball never dries out completely, no more. No feeding until spring growth begins.
What kills azolla pinnata over winter?
Bringing azolla pinnata into a warm living room. Too much winter warmth forces weak, pale growth that collapses when it goes back outside — cool and bright beats warm and dim.