Melon · Shanghai, Shanghai, China
When to plant melons in Shanghai
Main outdoor window
23 Mar - 6 Apr
The window this page is built around.
Timed from last spring frost
2 March
In Shanghai, on your chosen risk.
Ready to pick
1-21 Jun
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 Shanghai
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
2-16 Feb
Four weeks before your last frost, under cover or on a windowsill.
Plant out
23 Mar - 6 Apr
Three weeks after your last frost.
Harvest
1-21 Jun
Melons through the year
Against the frost risk in Shanghai
Why these dates
Plant out three weeks after last frost, not two. Black plastic mulch or a cloche raises soil temperature enough to make melons viable several hundred kilometres further north than they otherwise would be.
Melons stop growing below 15C and never fully recover. Frost is fatal, but the real limit is cool nights.
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. Melons are timed from 4 weeks before that frost for an indoor start, with planting out 3 weeks after it, and this page simply resolves those offsets against the frost date computed for Shanghai.
The median frost-free season here is 287 days, against 70 to 90 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Shanghai
Other vegetables to time
Growing melons in Shanghai
When should I plant melons in Shanghai?
Aim for 23 Mar - 6 Apr in an average year. If you would rather not gamble on the weather, wait until 4-18 Apr - by then frost has finished in nine years out of ten.
When will melons be ready to harvest in Shanghai?
Expect to start picking around 1-21 Jun, based on 70 to 90 days to maturity from the planting date calculated for this location.
How much frost will melons tolerate?
Melons stop growing below 15C and never fully recover. Frost is fatal, but the real limit is cool nights.