Cucumber · Lanzhou, Gansu, China
When to plant cucumbers in Lanzhou
Main outdoor window
14-28 May
The window this page is built around.
Timed from last spring frost
30 April
In Lanzhou, on your chosen risk.
Ready to pick
3-23 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 Lanzhou
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
9-23 Apr
Three weeks before your last frost, under cover or on a windowsill.
Sow direct
14-28 May
Two weeks after your last frost.
Plant out
14-28 May
Two weeks after your last frost.
Harvest
3-23 Jul
Cucumbers through the year
Against the frost risk in Lanzhou
Why these dates
Only three weeks indoors: cucumbers hate root disturbance, so sow into modules or pots you can plant whole. A second sowing three weeks after the first extends picking by a month.
Cold soil rots cucumber seed before it germinates. If soil is below 18C, wait - the seed is cheaper than the fortnight you would lose.
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. Cucumbers are timed from 3 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 Lanzhou.
The median frost-free season here is 168 days, against 50 to 70 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Lanzhou
Other vegetables to time
Growing cucumbers in Lanzhou
When should I plant cucumbers in Lanzhou?
Aim for 14-28 May in an average year. If you would rather not gamble on the weather, wait until 26 May - 9 Jun - by then frost has finished in nine years out of ten.
When will cucumbers be ready to harvest in Lanzhou?
Expect to start picking around 3-23 Jul, based on 50 to 70 days to maturity from the planting date calculated for this location.
How much frost will cucumbers tolerate?
Cold soil rots cucumber seed before it germinates. If soil is below 18C, wait - the seed is cheaper than the fortnight you would lose.