Spring onion · Yangzhou, Jiangsu, China
When to plant spring onions in Yangzhou
Main outdoor window
16 Feb - 2 Mar
The window this page is built around.
Timed from last spring frost
16 March
In Yangzhou, on your chosen risk.
Ready to pick
12 Apr - 2 May
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 Yangzhou
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 for overwintering
7-28 Aug
Counting back 89 days from your first frost so the crop matures in time.
Sow direct
16 Feb - 2 Mar
Four weeks before your last frost.
Harvest
12 Apr - 2 May
Spring onions through the year
Against the frost risk in Yangzhou
Why these dates
Sow direct every three weeks from four weeks before the last frost until about ten weeks before the first. An autumn sowing overwinters for a very early spring crop.
Tolerates about -8C. Autumn sowings survive most temperate winters and stand through cold weather without bolting.
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. Spring onions are timed for direct sowing 4 weeks before it, and this page simply resolves those offsets against the frost date computed for Yangzhou.
The median frost-free season here is 254 days, against 55 to 75 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Yangzhou
Other vegetables to time
Growing spring onions in Yangzhou
When should I plant spring onions in Yangzhou?
Aim for 16 Feb - 2 Mar in an average year. If you would rather not gamble on the weather, wait until 25 Feb - 11 Mar - by then frost has finished in nine years out of ten.
When will spring onions be ready to harvest in Yangzhou?
Expect to start picking around 12 Apr - 2 May, based on 55 to 75 days to maturity from the planting date calculated for this location.
How much frost will spring onions tolerate?
Tolerates about -8C. Autumn sowings survive most temperate winters and stand through cold weather without bolting.