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When to plant zinnias in zone 9a

In zone 9a, where the last spring frost typically comes around March 2, start zinnias indoors March 31 to April 7 and plant out April 28 to May 12.

The zone 9a schedule for zinnias

Start seeds indoors
March 31 to April 7
Plant out
April 28 to May 12
Sow outdoors
April 28 to May 12
Soil warm enough (70°F), about
April 28

From the median frost dates of the NOAA stations assigned to the 1,736 ZIP codes in zone 9a, and the timing recommended by Cooperative Extension guides for zinnias.

Frost risk in zone 9a

Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 9a, the typical last frost ranges from about February 13 in the earliest tenth of ZIP codes to March 21 in the latest tenth, and the first fall frost from November 14 to December 9. For a typical place in the zone:

  • February 4Risky: a later frost happens in 9 years out of 10
  • March 2Typical: frost after this date in half of years
  • March 25Safe: 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 9a cities

CityTypical last frostStart indoorsPlant out
Austin, TXFeb 20Mar 21 to 28Apr 18 to May 2
Seattle, WAMar 8Feb 8 to 15Mar 8 to 22
Portland, ORMar 13Jun 15 to 22Jul 13 to 27
Tucson, AZFeb 5Mar 28 to Apr 4Apr 25 to May 9
North Las Vegas, NVJan 20Mar 28 to Apr 4Apr 25 to May 9
Baton Rouge, LAFeb 25Mar 28 to Apr 4Apr 25 to May 9
Tallahassee, FLMar 11Mar 30 to Apr 6Apr 27 to May 11
Mobile, ALFeb 21Mar 27 to Apr 3Apr 24 to May 8
Palmdale, CAMar 10Apr 26 to May 3May 24 to Jun 7
Charleston, SCFeb 4Apr 3 to 10May 1 to 15
Savannah, GAMar 2Apr 2 to 9Apr 30 to May 14
Gainesville, FLMar 3Mar 26 to Apr 2Apr 23 to May 7

How to grow zinniasAll zonesZinnias in zone 8bZinnias in zone 9bAbout zone 9a

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