Garlic chives · Köln, North Rhine-Westphalia, Germany
When to plant garlic chives in Köln
Main outdoor window
10 Nov - 3 Apr
The window this page is built around.
Timed from last spring frost
17 April
In Köln, on your chosen risk.
Ready to pick
1 May - 31 Oct
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.
Plant divisions
10 Nov - 3 Apr
Any time the plant is dormant and the ground is neither frozen nor waterlogged: after leaf fall in autumn, or at the end of winter before growth restarts.
Harvest
1 May - 31 Oct
Garlic chives through the year
Against the frost risk in Köln
Why these dates
Sow or divide in spring. Cut the clump to 5cm whenever it gets tired and it regrows within three weeks, from early spring until hard frost.
Hardy to -20C. The clump dies back completely in winter and returns from the roots, so an empty patch in February is not a dead plant.
Garlic chives are planted once and then left in place, so there is no sowing offset to resolve. What matters in Köln is the shape of the year: this crop is dormant through the winter and is planted while it sleeps, any time between leaf fall in autumn and the restart of growth in spring, so long as the ground is neither frozen nor waterlogged. That is why the window below spans the cold months rather than sitting in the middle of the growing season.
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.
Growing garlic chives in Köln
When should I plant garlic chives in Köln?
Aim for 10 Nov - 3 Apr in an average year. If you would rather not gamble on the weather, wait until 17 Oct - 19 Apr - by then frost has finished in nine years out of ten.
When will garlic chives be ready to harvest in Köln?
Expect to start picking around 1 May - 31 Oct, based on 80 to 100 days to maturity from the planting date calculated for this location.
How much frost will garlic chives tolerate?
Hardy to -20C. The clump dies back completely in winter and returns from the roots, so an empty patch in February is not a dead plant.