Brussels sprouts · Hamhŭng, South Hamgyong, North Korea
When to plant brussels sprouts in Hamhŭng
Main outdoor window
20 Apr - 11 May
The window this page is built around.
Timed from last spring frost
20 April
In Hamhŭng, on your chosen risk.
Ready to pick
29 Jul - 28 Aug
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 Hamhŭng
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
9-30 Mar
Six weeks before your last frost, under cover or on a windowsill.
Plant out
20 Apr - 11 May
Around your last frost.
Harvest
29 Jul - 28 Aug
Brussels sprouts through the year
Against the frost risk in Hamhŭng
Why these dates
Sow in spring for a harvest that begins after the first autumn frosts. Rushing this crop to maturity in warm weather gives loose, bitter sprouts.
Improves after frost and stands through -12C. This is the clearest example of a crop where the first autumn frost is a target rather than a deadline.
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. Brussels sprouts are timed from 6 weeks before that frost for an indoor start, with planting out 0 weeks after it, and this page simply resolves those offsets against the frost date computed for Hamhŭng.
The median frost-free season here is 185 days, against 100 to 130 days to maturity for this crop counted from planting out. That margin is what decides whether a late sowing is worth attempting.
Also in Hamhŭng
Other vegetables to time
Growing brussels sprouts in Hamhŭng
When should I plant brussels sprouts in Hamhŭng?
Aim for 20 Apr - 11 May in an average year. If you would rather not gamble on the weather, wait until 26 Apr - 17 May - by then frost has finished in nine years out of ten.
When will brussels sprouts be ready to harvest in Hamhŭng?
Expect to start picking around 29 Jul - 28 Aug, based on 100 to 130 days to maturity from the planting date calculated for this location.
How much frost will brussels sprouts tolerate?
Improves after frost and stands through -12C. This is the clearest example of a crop where the first autumn frost is a target rather than a deadline.