Cornflower · Mianyang, Sichuan, China
When to sow cornflowers in Mianyang
Main outdoor window
4 Feb - 4 Mar
The window this page is built around.
Timed from last spring frost
25 February
In Mianyang, on your chosen risk.
Ready to pick
10-30 Apr
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 Mianyang
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
14 Jan - 11 Feb
Six weeks before your last frost, under cover or on a windowsill.
Sow direct
4 Feb - 4 Mar
Three weeks before your last frost.
Plant out
11 Feb - 11 Mar
Two weeks before your last frost.
In flower
10-30 Apr
Cornflowers through the year
Against the frost risk in Mianyang
Why these dates
Sow direct three weeks before the last frost, thinly and where it is to flower - it resents transplanting once the taproot is down. Deadhead relentlessly, because a plant allowed to set seed stops flowering within a fortnight. An autumn sowing gives much taller, sturdier plants.
Hardy to about -10C as a young plant, which is what makes autumn sowing possible in zone 7 and milder. Dislikes humid heat and finishes early in a hot summer.
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. Cornflowers 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 Mianyang.
Hardiness is not the obstacle here. Mianyang is zone 9a, 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 286 days, against 65 to 85 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Mianyang
Other flowers to time
Growing cornflowers in Mianyang
When should I plant cornflowers in Mianyang?
Aim for 4 Feb - 4 Mar in an average year. If you would rather not gamble on the weather, wait until 21 Feb - 21 Mar - by then frost has finished in nine years out of ten.
When will cornflowers be ready to harvest in Mianyang?
Expect to start picking around 10-30 Apr, based on 65 to 85 days to maturity from the planting date calculated for this location.
How much frost will cornflowers tolerate?
Hardy to about -10C as a young plant, which is what makes autumn sowing possible in zone 7 and milder. Dislikes humid heat and finishes early in a hot summer.