Growing Calendar

MenuClose

HomeAboutSearch

When to plant zinnias in zone 9b

In zone 9b, where the last spring frost typically comes around January 31, start zinnias indoors March 25 to April 1 and plant out April 22 to May 6.

The zone 9b schedule for zinnias

Start seeds indoors
March 25 to April 1
Plant out
April 22 to May 6
Sow outdoors
April 22 to May 6
Soil warm enough (70°F), about
April 22

From the median frost dates of the NOAA stations assigned to the 1,459 ZIP codes in zone 9b, and the timing recommended by Cooperative Extension guides for zinnias.

Frost risk in zone 9b

Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 9b, the typical last frost ranges from about January 12 in the earliest tenth of ZIP codes to March 1 in the latest tenth, and the first fall frost from January 8 to December 28. For a typical place in the zone:

  • December 18Risky: a later frost happens in 9 years out of 10
  • January 31Typical: frost after this date in half of years
  • March 1Safe: a later frost only 1 year in 10

Zinnias are killed by frost, so if you want to be safe, plant out after the safe date rather than the typical one, or be ready to cover plants on a cold night.

Your dates for zinnias

Set your ZIP code at the top of the page and we will work out when to plant zinnias where you live, from the frost records of the nearest NOAA weather station. Your ZIP code is remembered on this device only.

Enter your ZIP code

Zinnias in zone 9b cities

CityTypical last frostStart indoorsPlant out
Houston, TXJan 30Mar 16 to 23Apr 13 to 27
Jacksonville, FLFeb 1Mar 16 to 23Apr 13 to 27
San Jose, CAJan 12Dec 15 to 22Jan 12 to 26
Fresno, CAJan 14Apr 17 to 24May 15 to 29
Sacramento, CAJan 12Apr 30 to May 7May 28 to Jun 11
Bakersfield, CAJan 17Apr 14 to 21May 12 to 26
New Orleans, LAJan 24Mar 13 to 20Apr 10 to 24
Henderson, NVJan 20Mar 28 to Apr 4Apr 25 to May 9

How to grow zinniasAll zonesZinnias in zone 9aAbout zone 9b

Sources