Sweet potato · Xinxiang, Henan, China
When to plant sweet potatoes in Xinxiang
Main outdoor window
9-23 Apr
The window this page is built around.
Timed from last spring frost
19 March
In Xinxiang, on your chosen risk.
Ready to pick
8 Jul - 7 Aug
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 Xinxiang
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.
Plant out
9-23 Apr
Three weeks after your last frost.
Harvest
8 Jul - 7 Aug
Sweet potatoes through the year
Against the frost risk in Xinxiang
Why these dates
Plant slips three weeks after last frost into soil at 18C or above. In cool climates, black plastic mulch is the difference between a crop and a disappointment.
Damaged at 1C - even a near-frost harms the roots. Lift before the first frost, not after 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 potatoes are timed with planting out 3 weeks after it, and this page simply resolves those offsets against the frost date computed for Xinxiang.
The median frost-free season here is 243 days, against 90 to 120 days to maturity for this crop counted from planting out. That margin is what decides whether a late sowing is worth attempting.
Also in Xinxiang
Other vegetables to time
Growing sweet potatoes in Xinxiang
When should I plant sweet potatoes in Xinxiang?
Aim for 9-23 Apr in an average year. If you would rather not gamble on the weather, wait until 24 Apr - 8 May - by then frost has finished in nine years out of ten.
When will sweet potatoes be ready to harvest in Xinxiang?
Expect to start picking around 8 Jul - 7 Aug, based on 90 to 120 days to maturity from the planting date calculated for this location.
How much frost will sweet potatoes tolerate?
Damaged at 1C - even a near-frost harms the roots. Lift before the first frost, not after it.