Kale · Karaj, Alborz Province, Iran
When to plant kale in Karaj
Main outdoor window
17 Apr - 8 May
The window this page is built around.
Timed from last spring frost
1 May
In Karaj, on your chosen risk.
Ready to pick
11 Jun - 1 Jul
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 Karaj
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
20 Mar - 10 Apr
Six weeks before your last frost, under cover or on a windowsill.
Sow for overwintering
9-30 Jul
Counting back 89 days from your first frost so the crop matures in time.
Sow direct
17 Apr - 8 May
Two weeks before your last frost.
Plant out
17 Apr - 8 May
Two weeks before your last frost.
Harvest
11 Jun - 1 Jul
Kale through the year
Against the frost risk in Karaj
Why these dates
Spring sowings feed you through summer; the sowing made twelve weeks before first frost is the one that carries you through winter.
Survives -12C and sweetens markedly below freezing as starches convert to sugars. Frost is a feature of this crop, not a threat.
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. Kale 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 Karaj.
The median frost-free season here is 179 days, against 55 to 75 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Karaj
Other vegetables to time
Growing kale in Karaj
When should I plant kale in Karaj?
Aim for 17 Apr - 8 May in an average year. If you would rather not gamble on the weather, wait until 3-24 May - by then frost has finished in nine years out of ten.
When will kale be ready to harvest in Karaj?
Expect to start picking around 11 Jun - 1 Jul, based on 55 to 75 days to maturity from the planting date calculated for this location.
How much frost will kale tolerate?
Survives -12C and sweetens markedly below freezing as starches convert to sugars. Frost is a feature of this crop, not a threat.