Flower · Asteraceae
When to sow calendulas
The easiest annual there is, and edible into the bargain - the petals go into salads and were once used to colour butter. Flowers within eight weeks of sowing and self-seeds freely enough to become permanent.
Start seed indoors
6 weeks before
Counted from your last spring frost.
Plant out
2 weeks before
Counted from your last spring frost.
Sow direct
3 weeks before
Counted from your last spring frost.
Those weeks become real dates once you name a place.
Timing, in frost-relative terms
Seed packets rarely give calendar dates, because a date that suits one latitude is wrong at another. They give offsets from the last spring frost instead, and those offsets are what make calendulas plantable anywhere.
- Start seed indoors 6 weeks before the last frost.
- Plant out 2 weeks before the last frost.
- Sow direct 3 weeks before the last frost.
- Expect 55–70 days to maturity, counted from sowing.
- Hardy in USDA zones 2a–11a.
- Sow again every 21 days for a continuous supply.
Getting the timing right
Sow direct three weeks before the last frost, or start indoors six weeks before it for the earliest flowers. Sow again every three weeks until midsummer for continuous bloom. In mild winters an autumn sowing overwinters as a small rosette and flowers a month earlier than anything sown in spring.
Frost tolerance
Takes light frost to about -8C without stopping, and often flowers straight through a mild winter in zone 9 and warmer. Heat is the greater enemy: it sulks and mildews above 30C and is best treated as a spring and autumn flower in hot climates.
Classified as hardy, with damage expected below -8°C (17.6°F)17.6°F (-8°C).