Sweetcorn · Laiwu, Shandong, China
When to plant sweetcorn in Laiwu
Main outdoor window
11-25 Apr
The window this page is built around.
Timed from last spring frost
4 April
In Laiwu, on your chosen risk.
Ready to pick
10 Jun - 20 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 Laiwu
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.
Sow direct
11-25 Apr
One week after your last frost.
Harvest
10 Jun - 20 Jul
Sweetcorn through the year
Against the frost risk in Laiwu
Why these dates
Seed rots in cold wet soil. Sowing a week after last frost into 15C soil beats sowing on the frost date into 10C soil almost every time.
Seedlings survive a very light frost if the growing point is still below soil level, but growth stalls. Mature plants are killed outright.
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. Sweetcorn are timed for direct sowing 1 weeks after it, and this page simply resolves those offsets against the frost date computed for Laiwu.
The median frost-free season here is 217 days, against 60 to 100 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Laiwu
Other vegetables to time
Growing sweetcorn in Laiwu
When should I plant sweetcorn in Laiwu?
Aim for 11-25 Apr in an average year. If you would rather not gamble on the weather, wait until 23 Apr - 7 May - by then frost has finished in nine years out of ten.
When will sweetcorn be ready to harvest in Laiwu?
Expect to start picking around 10 Jun - 20 Jul, based on 60 to 100 days to maturity from the planting date calculated for this location.
How much frost will sweetcorn tolerate?
Seedlings survive a very light frost if the growing point is still below soil level, but growth stalls. Mature plants are killed outright.