Overwintering guide
How to overwinter cosmos
Winter watering
If you do keep it going indoors, water sparingly — just enough that the compost never dries out completely — and do not feed until growth restarts in spring.
The mistake that kills cosmos in winter
Leaving cosmos outside over winter expecting it back in spring. As an annual it will not return — seed or cuttings are the only way to carry it forward.
More cosmos care
Overwintering cosmos — FAQ
Does cosmos need to come indoors for winter?
Cosmos is grown as an annual — it is frost-tender and naturally finishes at the end of the season, whatever your zone. In most climates cosmos is grown as an annual, so there is usually nothing to overwinter — the plant completes its life cycle and dies back with the first frosts. If you want to carry it over, lift it before the first frost and grow it on in the brightest window you have, or take cuttings; otherwise collect seed and start fresh in spring, which is what most growers do.
When should I move cosmos for winter?
Lift or take cuttings before the first frost — or let it finish and save seed.
How often should I water cosmos in winter?
If you do keep it going indoors, water sparingly — just enough that the compost never dries out completely — and do not feed until growth restarts in spring.
What kills cosmos over winter?
Leaving cosmos outside over winter expecting it back in spring. As an annual it will not return — seed or cuttings are the only way to carry it forward.