Lemon balm · Hyesan, Yanggang-do, North Korea
When to plant lemon balm in Hyesan
Main outdoor window
1-22 May
The window this page is built around.
Timed from last spring frost
15 May
In Hyesan, 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 Hyesan
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
Eight weeks before your last frost, under cover or on a windowsill.
Sow direct
1-22 May
Two weeks before your last frost.
Plant out
29 May - 19 Jun
Two weeks after your last frost.
Harvest
1 May - 31 Oct
Lemon balm through the year
Against the frost risk in Hyesan
Why these dates
Extremely hardy, to about -25C. Dies to the ground and returns reliably.
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. Lemon balm are timed from 8 weeks before that frost for an indoor start, with planting out 2 weeks after it, and this page simply resolves those offsets against the frost date computed for Hyesan.
Hardiness is not the obstacle here. Hyesan is zone 4b, comfortably inside the range this crop is rated for, so an established plant should come through an average winter without protection.
Do not expect a crop in the first year. A plant set out now should give its first worthwhile pick around year 1, and will then produce every year after that, which is what makes the planting decision worth getting right the first time.
Growing lemon balm in Hyesan
When should I plant lemon balm in Hyesan?
Aim for 1-22 May in an average year. If you would rather not gamble on the weather, wait until 13 May - 3 Jun - by then frost has finished in nine years out of ten.
When will lemon balm be ready to harvest in Hyesan?
Expect to start picking around 1 May - 31 Oct, based on 70 to 90 days to maturity from the planting date calculated for this location.
How much frost will lemon balm tolerate?
Extremely hardy, to about -25C. Dies to the ground and returns reliably.