Marigold · Shuangcheng, Heilongjiang, China
When to sow marigolds in Shuangcheng
Main outdoor window
3-17 May
The window this page is built around.
Timed from last spring frost
26 April
In Shuangcheng, on your chosen risk.
Ready to pick
22 Jun - 12 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 Shuangcheng
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
15-29 Mar
Six weeks before your last frost, under cover or on a windowsill.
Sow direct
3-17 May
One week after your last frost.
Plant out
3-17 May
One week after your last frost.
In flower
22 Jun - 12 Jul
Marigolds through the year
Against the frost risk in Shuangcheng
Why these dates
Six weeks indoors produces flowering plants at transplant time. Direct sowing works but flowers three weeks later.
Killed by frost at both ends of the season, with no tolerance at any growth stage.
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. Marigolds are timed from 6 weeks before that frost for an indoor start, with planting out 1 weeks after it, and this page simply resolves those offsets against the frost date computed for Shuangcheng.
The median frost-free season here is 162 days, against 50 to 70 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Shuangcheng
Other flowers to time
Growing marigolds in Shuangcheng
When should I plant marigolds in Shuangcheng?
Aim for 3-17 May in an average year. If you would rather not gamble on the weather, wait until 12-26 May - by then frost has finished in nine years out of ten.
When will marigolds be ready to harvest in Shuangcheng?
Expect to start picking around 22 Jun - 12 Jul, based on 50 to 70 days to maturity from the planting date calculated for this location.
How much frost will marigolds tolerate?
Killed by frost at both ends of the season, with no tolerance at any growth stage.