Safe to Plant

Zinnia · Shuozhou, Shanxi, China

When to sow zinnias in Shuozhou

Main outdoor window

15-29 May

The window this page is built around.

Timed from last spring frost

8 May

In Shuozhou, on your chosen risk.

Ready to pick

14 Jul - 3 Aug

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 Shuozhou

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

10-24 Apr

Four weeks before your last frost, under cover or on a windowsill.

Sow direct

15-29 May

One week after your last frost.

Plant out

15-29 May

One week after your last frost.

In flower

14 Jul - 3 Aug

Sow in succession. A single sowing gives you a single glut. Sow a short row every 21 days through the window above and you get a steady supply instead.
Frost tolerance
Tender
Damaged below
0°C (32°F)
Days to flowering
60–80
Min soil temp
21°C (69.8°F)
Spacing
25 cm
Sowing depth
6 mm (0.2 in)
Sun
Full

Zinnias through the year

Against the frost risk in Shuozhou

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Frost risk Start indoors Sow direct Plant out Harvest Today

Why these dates

Direct sowing after last frost usually beats transplanting - zinnias dislike root disturbance and catch up quickly.

Killed by the first frost at either end of the season. Strictly a warm-season flower.

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. Zinnias are timed from 4 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 Shuozhou.

The median frost-free season here is 147 days, against 60 to 80 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.

See every crop timed for Shuozhou →

Growing zinnias in Shuozhou

When should I plant zinnias in Shuozhou?

Aim for 15-29 May in an average year. If you would rather not gamble on the weather, wait until 23 May - 6 Jun - by then frost has finished in nine years out of ten.

When will zinnias be ready to harvest in Shuozhou?

Expect to start picking around 14 Jul - 3 Aug, based on 60 to 80 days to maturity from the planting date calculated for this location.

How much frost will zinnias tolerate?

Killed by the first frost at either end of the season. Strictly a warm-season flower.