Calendula · León de los Aldama, Guanajuato, Mexico
When to sow calendulas in León de los Aldama
Main outdoor window
27 Dec - 24 Jan
The window this page is built around.
Timed from last spring frost
17 January
In León de los Aldama, on your chosen risk.
Ready to pick
20 Feb - 7 Mar
If you plant at the start of the window.
The average last frost. Half of all years are later than this.
Step by step in León de los Aldama
Each window is a range, not a single day. Earlier in the range buys you a longer season; later in it buys you a safer one.
Start indoors
6 Dec - 3 Jan
Six weeks before your last frost, under cover or on a windowsill.
Sow direct
27 Dec - 24 Jan
Three weeks before your last frost.
Plant out
3-31 Jan
Two weeks before your last frost.
In flower
20 Feb - 7 Mar
Calendulas through the year
Against the frost risk in León de los Aldama
Why these dates
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.
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.
Seed packets and extension guides express timing as weeks either side of the last spring frost, because that is the only reference point that travels. Calendulas are timed from 6 weeks before that frost for an indoor start, with planting out 2 weeks before it, and this page simply resolves those offsets against the frost date computed for León de los Aldama.
Hardiness is not the obstacle here. León de los Aldama is zone 10a, comfortably inside the range this crop is rated for, so an established plant should come through an average winter without protection.
The median frost-free season here is 329 days, against 55 to 70 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Growing calendulas in León de los Aldama
When should I plant calendulas in León de los Aldama?
Aim for 27 Dec - 24 Jan in an average year. If you would rather not gamble on the weather, wait until 28 Jan - 25 Feb - by then frost has finished in nine years out of ten.
When will calendulas be ready to harvest in León de los Aldama?
Expect to start picking around 20 Feb - 7 Mar, based on 55 to 70 days to maturity from the planting date calculated for this location.
How much frost will calendulas tolerate?
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.