Shirley poppy · Columbia, Missouri, United States
When to sow shirley poppies in Columbia
Main outdoor window
16 Mar - 6 Apr
The window this page is built around.
Timed from last spring frost
13 April
In Columbia, on your chosen risk.
Ready to pick
15 May - 4 Jun
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 Columbia
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.
Sow direct
16 Mar - 6 Apr
Four weeks before your last frost.
In flower
15 May - 4 Jun
Shirley poppies through the year
Against the frost risk in Columbia
Why these dates
Sow direct four weeks before the last frost, on the surface with no covering - the seed needs light to germinate and disappears if raked in. Sowing onto snow or frosted ground works well and spaces the seed for you. It cannot be transplanted at any size, so sow where it is to flower.
Hardy to about -12C and germinates in cold soil, so it is a natural for autumn or late-winter sowing. Ends abruptly in the first real heat of 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. Shirley poppies are timed for direct sowing 4 weeks before it, and this page simply resolves those offsets against the frost date computed for Columbia.
Hardiness is not the obstacle here. Columbia is zone 6b, 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 197 days, against 60 to 80 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Nearby
Shirley poppies in places close by
Also in Columbia
Other flowers to time
Growing shirley poppies in Columbia
When should I plant shirley poppies in Columbia?
Aim for 16 Mar - 6 Apr in an average year. If you would rather not gamble on the weather, wait until 27 Mar - 17 Apr - by then frost has finished in nine years out of ten.
When will shirley poppies be ready to harvest in Columbia?
Expect to start picking around 15 May - 4 Jun, based on 60 to 80 days to maturity from the planting date calculated for this location.
How much frost will shirley poppies tolerate?
Hardy to about -12C and germinates in cold soil, so it is a natural for autumn or late-winter sowing. Ends abruptly in the first real heat of summer.