Swiss chard · Gunpo, Gyeonggi-do, South Korea
When to plant swiss chard in Gunpo
Main outdoor window
20 Mar - 10 Apr
The window this page is built around.
Timed from last spring frost
3 April
In Gunpo, on your chosen risk.
Ready to pick
9-19 May
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 Gunpo
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
27 Feb - 20 Mar
Five weeks before your last frost, under cover or on a windowsill.
Sow for overwintering
9-30 Aug
Counting back 74 days from your first frost so the crop matures in time.
Sow direct
20 Mar - 10 Apr
Two weeks before your last frost.
Plant out
27 Mar - 17 Apr
One week before your last frost.
Harvest
9-19 May
Swiss chard through the year
Against the frost risk in Gunpo
Why these dates
One spring sowing usually lasts until hard frost. In mild climates it overwinters and produces an early spring flush before bolting.
Takes -5C without protection. Under a cloche it will hold through much colder weather and resume growth in late winter.
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. Swiss chard are timed from 5 weeks before that frost for an indoor start, with planting out 1 weeks before it, and this page simply resolves those offsets against the frost date computed for Gunpo.
The median frost-free season here is 223 days, against 50 to 60 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Gunpo
Other vegetables to time
Growing swiss chard in Gunpo
When should I plant swiss chard in Gunpo?
Aim for 20 Mar - 10 Apr in an average year. If you would rather not gamble on the weather, wait until 29 Mar - 19 Apr - by then frost has finished in nine years out of ten.
When will swiss chard be ready to harvest in Gunpo?
Expect to start picking around 9-19 May, based on 50 to 60 days to maturity from the planting date calculated for this location.
How much frost will swiss chard tolerate?
Takes -5C without protection. Under a cloche it will hold through much colder weather and resume growth in late winter.