Tomato · Nanjing, Jiangsu, China
When to plant tomatoes in Nanjing
Main outdoor window
28 Mar - 18 Apr
The window this page is built around.
Timed from last spring frost
14 March
In Nanjing, on your chosen risk.
Ready to pick
27 May - 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 Nanjing
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
31 Jan - 21 Feb
Six weeks before your last frost, under cover or on a windowsill.
Plant out
28 Mar - 18 Apr
Two weeks after your last frost.
Harvest
27 May - 21 Jun
Tomatoes through the year
Against the frost risk in Nanjing
Why these dates
Six weeks of indoor growing produces a stocky transplant with a first flower truss forming. Starting earlier than eight weeks usually backfires: the plant becomes leggy and root-bound, and gains nothing on a plant sown later.
Tomato foliage is damaged at 0C and killed outright at about -1C. There is no recovery from a frosted plant, so the transplant date is the single most consequential decision in the tomato year.
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. Tomatoes are timed from 6 weeks before that frost for an indoor start, with planting out 2 weeks after it, and this page simply resolves those offsets against the frost date computed for Nanjing.
The median frost-free season here is 258 days, against 60 to 85 days to maturity for this crop counted from planting out. That margin is what decides whether a late sowing is worth attempting.
Also in Nanjing
Other vegetables to time
Growing tomatoes in Nanjing
When should I plant tomatoes in Nanjing?
Aim for 28 Mar - 18 Apr in an average year. If you would rather not gamble on the weather, wait until 9-30 Apr - by then frost has finished in nine years out of ten.
When will tomatoes be ready to harvest in Nanjing?
Expect to start picking around 27 May - 21 Jun, based on 60 to 85 days to maturity from the planting date calculated for this location.
How much frost will tomatoes tolerate?
Tomato foliage is damaged at 0C and killed outright at about -1C. There is no recovery from a frosted plant, so the transplant date is the single most consequential decision in the tomato year.