Sweet pea · Deyang, Sichuan, China
When to sow sweet peas in Deyang
Main outdoor window
3-24 Jan
The window this page is built around.
Timed from last spring frost
14 February
In Deyang, on your chosen risk.
Ready to pick
3-23 Apr
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 Deyang
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
5-26 Dec
Ten weeks before your last frost, under cover or on a windowsill.
Sow for overwintering
18 Jul - 8 Aug
Counting back 124 days from your first frost so the crop matures in time.
Sow direct
3-24 Jan
Six weeks before your last frost.
Plant out
17 Jan - 7 Feb
Four weeks before your last frost.
In flower
3-23 Apr
Sweet peas through the year
Against the frost risk in Deyang
Why these dates
Sow in autumn and overwinter in a cold frame in zone 6 and warmer, or start ten weeks before last frost. Pinch at four true leaves.
Young plants take -8C and benefit from the cold. This is a flower where autumn sowing genuinely doubles the season.
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 peas are timed from 10 weeks before that frost for an indoor start, with planting out 4 weeks before it, and this page simply resolves those offsets against the frost date computed for Deyang.
The median frost-free season here is 300 days, against 90 to 110 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Growing sweet peas in Deyang
When should I plant sweet peas in Deyang?
Aim for 3-24 Jan in an average year. If you would rather not gamble on the weather, wait until 28 Jan - 18 Feb - by then frost has finished in nine years out of ten.
When will sweet peas be ready to harvest in Deyang?
Expect to start picking around 3-23 Apr, based on 90 to 110 days to maturity from the planting date calculated for this location.
How much frost will sweet peas tolerate?
Young plants take -8C and benefit from the cold. This is a flower where autumn sowing genuinely doubles the season.