Crocus · Minhang, Shanghai, China
When to sow crocuses in Minhang
Main outdoor window
1-15 Nov
The window this page is built around.
Timed from last spring frost
2 March
In Minhang, on your chosen risk.
Ready to pick
1 Feb - 31 Mar
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 Minhang
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 the corms
1-15 Nov
Four to six weeks before your first frost, so roots form before the ground cools.
In flower
1 Feb - 31 Mar
Crocuses through the year
Against the frost risk in Minhang
Why these dates
Plant in early autumn, six to eight weeks before the first frost, 8cm deep. Naturalising in grass is the best use of them: they flower and set seed before the first cut of the season is due, so the lawn can be left uncut until the leaves yellow in late spring.
Hardy to -30C and among the most frost-indifferent flowers grown - blooms freeze solid overnight and reopen the same morning. Needs a cold winter to flower well and fails in zone 9 and warmer.
Crocuses are anchored to the first autumn frost rather than the last spring one, so the planting window on this page counts backwards from the end of the season in Minhang instead of forwards from its start.
Minhang sits in zone 9a, which is milder than this crop wants, and a winter that never really arrives is its own problem. The dates below still describe the right time of year; the open question is survival rather than timing.
The median frost-free season here is 287 days, against 120 to 170 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Minhang
Other flowers to time
Growing crocuses in Minhang
When should I plant crocuses in Minhang?
Aim for 1-15 Nov in an average year. If you would rather not gamble on the weather, wait until 14-28 Oct - by then frost has finished in nine years out of ten.
When will crocuses be ready to harvest in Minhang?
Expect to start picking around 1 Feb - 31 Mar, based on 120 to 170 days to maturity from the planting date calculated for this location.
How much frost will crocuses tolerate?
Hardy to -30C and among the most frost-indifferent flowers grown - blooms freeze solid overnight and reopen the same morning. Needs a cold winter to flower well and fails in zone 9 and warmer.