Sweet pepper · Osan, Gyeonggi-do, South Korea
When to plant sweet peppers in Osan
Main outdoor window
12 Apr - 3 May
The window this page is built around.
Timed from last spring frost
29 March
In Osan, on your chosen risk.
Ready to pick
11 Jun - 11 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 Osan
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
1-22 Feb
Eight weeks before your last frost, under cover or on a windowsill.
Plant out
12 Apr - 3 May
Two weeks after your last frost.
Harvest
11 Jun - 11 Jul
Sweet peppers through the year
Against the frost risk in Osan
Why these dates
Peppers germinate slowly and unevenly below 24C, so start them two weeks ahead of tomatoes. Bottom heat makes a bigger difference here than for any other common vegetable.
Frost kills peppers outright, but the more common failure is chilling injury: a week of nights near 5C stunts a young plant for the rest of the season without visibly damaging it.
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. Sweet peppers 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 Osan.
The median frost-free season here is 234 days, against 60 to 90 days to maturity for this crop counted from planting out. That margin is what decides whether a late sowing is worth attempting.
Also in Osan
Other vegetables to time
Growing sweet peppers in Osan
When should I plant sweet peppers in Osan?
Aim for 12 Apr - 3 May in an average year. If you would rather not gamble on the weather, wait until 22 Apr - 13 May - by then frost has finished in nine years out of ten.
When will sweet peppers be ready to harvest in Osan?
Expect to start picking around 11 Jun - 11 Jul, based on 60 to 90 days to maturity from the planting date calculated for this location.
How much frost will sweet peppers tolerate?
Frost kills peppers outright, but the more common failure is chilling injury: a week of nights near 5C stunts a young plant for the rest of the season without visibly damaging it.