Godetia · Köln, North Rhine-Westphalia, Germany
When to sow godetias in Köln
Main outdoor window
27 Mar - 17 Apr
The window this page is built around.
Timed from last spring frost
17 April
In Köln, on your chosen risk.
Ready to pick
10-30 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 Köln
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
27 Mar - 17 Apr
Three weeks before your last frost.
In flower
10-30 Jun
Godetias through the year
Against the frost risk in Köln
Why these dates
Sow direct three weeks before the last frost, thinly, on unimproved ground - rich soil gives leaves instead of flowers. Do not thin too hard; it flowers better standing slightly crowded and supports itself that way. Needs cool nights to set buds, so late sowings in a hot climate rarely amount to much.
Hardy to about -8C as a seedling. It is a plant of cool maritime summers, so autumn sowing suits zone 8 and 9 well while hot inland summers defeat it whenever it is sown.
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. Godetias are timed for direct sowing 3 weeks before it, and this page simply resolves those offsets against the frost date computed for Köln.
Hardiness is not the obstacle here. Köln is zone 8a, 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 207 days, against 75 to 95 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Köln
Other flowers to time
Growing godetias in Köln
When should I plant godetias in Köln?
Aim for 27 Mar - 17 Apr in an average year. If you would rather not gamble on the weather, wait until 12 Apr - 3 May - by then frost has finished in nine years out of ten.
When will godetias be ready to harvest in Köln?
Expect to start picking around 10-30 Jun, based on 75 to 95 days to maturity from the planting date calculated for this location.
How much frost will godetias tolerate?
Hardy to about -8C as a seedling. It is a plant of cool maritime summers, so autumn sowing suits zone 8 and 9 well while hot inland summers defeat it whenever it is sown.