US Grow Zones

USDA hardiness zone 9a

In zone 9a, the average annual extreme minimum temperature is 20 to 25°F (-6.7 to -3.9°C), based on 1991–2020 data from the 2023 USDA Plant Hardiness Zone Map.

Temperature range20 to 25°F-6.7 to -3.9°C
ZIP codes2,199in this half-zone
Major cities35on this site
Typical last frostMar 1130% risk

What zone 9a means for your garden

A plant labeled "hardy to zone 9a" should survive a typical winter low of 20°F. Tropical and subtropical plants are an option, but many temperate fruit trees may not get enough winter chill. Zone 9b is the warmer half of zone 9.

ZIP codes in zone 9a: 2,199 in contiguous U.S..

Frost dates in zone 9a

Across 34 major cities in zone 9a, the 30%-risk last spring frost ranges from Feb 4 to Apr 11 (median Mar 11), and the first fall frost has a median of Nov 19. In 1 more cities frost is rare. Frost timing depends on elevation, latitude and distance from water — a zone does not set a frost date, so check your city page for local dates.

Typical planting calendar for zone 9a

Based on the median frost dates above. For your exact dates, use your city page.

CropStart indoorsTransplant / plant outDirect sowFall crop sow/plant
TomatoJan 14 – Jan 28Mar 18 – Apr 1——
PepperDec 31 – Jan 14Mar 25 – Apr 8——
LettuceJan 28 – Feb 11Feb 25 – Mar 18Feb 11 – Mar 25Sep 10 – Oct 8
Green Beans——Mar 18 – Apr 22Aug 27 – Sep 10
Sweet Corn——Mar 18 – Apr 15—
Zucchini & Summer SquashFeb 11 – Feb 18Mar 18 – Apr 1Mar 18 – Apr 8Aug 27 – Sep 10
CucumberFeb 11 – Feb 18Mar 25 – Apr 1Mar 18 – Apr 8Aug 27 – Sep 10
Carrot——Feb 18 – Mar 25Aug 27 – Sep 10
OnionDec 17 – Dec 31Feb 11 – Feb 25——
Potato—Feb 11 – Mar 4——
BasilJan 28 – Feb 11Mar 25 – Apr 8Mar 25 – Apr 15—
Spinach——Jan 28 – Feb 25Sep 24 – Oct 22
KaleJan 14 – Jan 28Feb 11 – Mar 4Feb 11 – Mar 4Sep 10 – Oct 8
BroccoliJan 14 – Jan 28Feb 25 – Mar 18—Aug 27 – Sep 10
Peas——Jan 28 – Feb 18Sep 10 – Sep 24
EggplantDec 31 – Jan 14Mar 25 – Apr 8——
CabbageJan 14 – Jan 28Feb 11 – Feb 25—Aug 27 – Sep 10
Radish——Feb 4 – Mar 25Oct 8 – Nov 5
Strawberry—Feb 11 – Mar 4——
Beets——Feb 18 – Apr 1Sep 10 – Sep 24

Cities in zone 9a (35)

Major cities whose center falls in zone 9a:

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