Hardiness zone

Zone 9b

The coldest winter night here averages 25 to 30°F1. Frost dates vary more than that suggests.

ZIP codes: 2,085
Weather stations: 344
Last reviewed: 2026-11-02

Photo: Alexander Aubin / Pexels

Your zone tells you how cold winter gets. It does not tell you when to plant.

Typical last frost: Feb 2most ZIPs Jan 12 – Feb 26
Typical first frost: Dec 14most ZIPs Nov 30 – Jan 5
Spread in spring: 45 daysbetween early and late ZIPs

Last spring frostmedian Feb 2Full range across the zone: Jan 1 to May 16Most of the zone (10th to 90th percentile): Jan 12 to Feb 26Zone median: Feb 2
First fall frostmedian Dec 14Full range across the zone: Oct 9 to Jan 30Most of the zone (10th to 90th percentile): Nov 30 to Jan 5Zone median: Dec 14

Frost-free season (median)

Figure 1. When frosts fall across zone 9b: the full range (pale), most ZIP codes (10th to 90th percentile, solid) and the median (marker). From 344 NOAA stations matched to 1,365 ZIP codes.

Zone and frost date are different things. The zone comes from the coldest winter night; frost dates come from spring and fall temperatures at weather stations2. Your own dates can sit anywhere in the range above, so the calendar for your ZIP is the better guide.

When to plant in zone 9b

Each crop uses its primary extension source, applied to this zone's frost spread. Rules written for another state are labelled with their source.

TomatoesStart indoors across most of the zone: Nov 17 to Jan 1Start indoors at the zone median: Dec 8 (Oregon State, central OR)Transplant outdoors across most of the zone: Jan 26 to Mar 11Transplant outdoors at the zone median: Feb 16 (Colorado State)Plant for fall across most of the zone: Aug 24 to Oct 13Plant for fall at the zone median: Sep 7 to Sep 21 (Texas A&M (E-502))
PeppersStart indoors across most of the zone: Dec 1 to Jan 15Start indoors at the zone median: Dec 22 (Oregon State, central OR)Transplant outdoors across most of the zone: Jan 26 to Mar 11Transplant outdoors at the zone median: Feb 16 (Colorado State)Plant for fall across most of the zone: Aug 10 to Oct 13Plant for fall at the zone median: Aug 24 to Sep 21 (Texas A&M (E-502))
CucumbersStart indoors across most of the zone: Dec 29 to Feb 12Start indoors at the zone median: Jan 19 (Oregon State, central OR)Transplant outdoors across most of the zone: Jan 19 to Mar 4Transplant outdoors at the zone median: Feb 9 (Oregon State, central OR)Sow outdoors across most of the zone: Jan 12 to Feb 26Sow outdoors at the zone median: Feb 2 (Colorado State)Plant for fall across most of the zone: Sep 7 to Oct 27Plant for fall at the zone median: Sep 21 to Oct 5 (Texas A&M (E-502))
ZucchiniStart indoors across most of the zone: Jan 5 to Feb 19Start indoors at the zone median: Jan 26 (Oregon State, central OR)Transplant outdoors across most of the zone: Jan 26 to Mar 11Transplant outdoors at the zone median: Feb 16 (Oregon State, central OR)Sow outdoors across most of the zone: Jan 12 to Feb 26Sow outdoors at the zone median: Feb 2 (Colorado State)Plant for fall across most of the zone: Aug 17 to Oct 13Plant for fall at the zone median: Aug 31 to Sep 21 (Texas A&M (E-502))
BeansStart indoors across most of the zone: Dec 22 to Feb 5Start indoors at the zone median: Jan 12 (Oregon State, central OR)Transplant outdoors across most of the zone: Jan 19 to Mar 4Transplant outdoors at the zone median: Feb 9 (Oregon State, central OR)Sow outdoors across most of the zone: Jan 12 to Feb 26Sow outdoors at the zone median: Feb 2 (Colorado State)Plant for fall across most of the zone: Sep 21 to Nov 10Plant for fall at the zone median: Oct 5 to Oct 19 (Texas A&M (E-502))Plant for fall across most of the zone: Aug 10 to Sep 29Plant for fall at the zone median: Aug 24 to Sep 7 (Texas A&M (E-502))
PeasStart indoors across most of the zone: Nov 17 to Jan 1Start indoors at the zone median: Dec 8 (Oregon State, central OR)Transplant outdoors across most of the zone: Dec 15 to Jan 29Transplant outdoors at the zone median: Jan 5 (Oregon State, central OR)Sow outdoors across most of the zone: Dec 15 to Feb 12Sow outdoors at the zone median: Jan 5 to Jan 19 (Colorado State)Plant for fall across most of the zone: Sep 7 to Dec 22Plant for fall at the zone median: Sep 21 to Nov 30 (Texas A&M (E-502))
LettuceStart indoors across most of the zone: Nov 24 to Jan 8Start indoors at the zone median: Dec 15 (Oregon State, central OR)Transplant outdoors across most of the zone: Dec 29 to Feb 12Transplant outdoors at the zone median: Jan 19 (Oregon State, central OR)Sow outdoors across most of the zone: Dec 15 to Feb 12Sow outdoors at the zone median: Jan 5 to Jan 19 (Colorado State)Plant for fall across most of the zone: Aug 24 to Oct 27Plant for fall at the zone median: Sep 7 to Oct 5 (Texas A&M (E-502))
CarrotsSow outdoors across most of the zone: Dec 29 to Feb 26Sow outdoors at the zone median: Jan 19 to Feb 2 (Colorado State)Plant for fall across most of the zone: Aug 24 to Oct 13Plant for fall at the zone median: Sep 7 to Sep 21 (Texas A&M (E-502))
OnionsStart indoors across most of the zone: Sep 22 to Nov 6Start indoors at the zone median: Oct 13 (Oregon State, central OR)Transplant outdoors across most of the zone: Dec 1 to Jan 15Transplant outdoors at the zone median: Dec 22 (Oregon State, central OR)Sow outdoors across most of the zone: Dec 15 to Feb 12Sow outdoors at the zone median: Jan 5 to Jan 19 (Colorado State)Plant for fall across most of the zone: Sep 21 to Nov 10Plant for fall at the zone median: Oct 5 to Oct 19 (Texas A&M (E-502))
GarlicPlant for fall across most of the zone: Dec 7 to Jan 19Plant for fall at the zone median: Dec 21 to Dec 28 (Wisconsin)
PotatoesSow outdoors across most of the zone: Dec 29 to Feb 26Sow outdoors at the zone median: Jan 19 to Feb 2 (Colorado State)Plant for fall across most of the zone: Aug 10 to Sep 29Plant for fall at the zone median: Aug 24 to Sep 7 (Texas A&M (E-502))
BasilNo sourced window

Start indoors
Plant outdoors
Range across the zone
Frost-free season (median)
Spring frost risk (90% to 10%)
Fall frost risk (10% to 90%)

Figure 2. Planting windows across zone 9b. Solid and dashed bars: the window at the zone's median frost dates. Pale bars: where the same window falls across most of the zone's ZIP codes.

Table 1. Planting windows in zone 9b.
Crop	What	Zone median	Across most of the zone	Source
Tomatoes	Start indoors	Dec 8	Nov 17 – Jan 1	Oregon State, central OR3
	Transplant outdoors	Feb 16	Jan 26 – Mar 11	Colorado State4
	Plant for fall	Sep 7 – Sep 21	Aug 24 – Oct 13	Texas A&M (E-502)5
Peppers	Start indoors	Dec 22	Dec 1 – Jan 15	Oregon State, central OR3
	Transplant outdoors	Feb 16	Jan 26 – Mar 11	Colorado State4
	Plant for fall	Aug 24 – Sep 21	Aug 10 – Oct 13	Texas A&M (E-502)5
Cucumbers	Start indoors	Jan 19	Dec 29 – Feb 12	Oregon State, central OR3
	Transplant outdoors	Feb 9	Jan 19 – Mar 4	Oregon State, central OR3
	Sow outdoors	Feb 2	Jan 12 – Feb 26	Colorado State4
	Plant for fall	Sep 21 – Oct 5	Sep 7 – Oct 27	Texas A&M (E-502)5
Zucchini	Start indoors	Jan 26	Jan 5 – Feb 19	Oregon State, central OR3
	Transplant outdoors	Feb 16	Jan 26 – Mar 11	Oregon State, central OR3
	Sow outdoors	Feb 2	Jan 12 – Feb 26	Colorado State4
	Plant for fall	Aug 31 – Sep 21	Aug 17 – Oct 13	Texas A&M (E-502)5
Beans	Start indoors	Jan 12	Dec 22 – Feb 5	Oregon State, central OR3
	Transplant outdoors	Feb 9	Jan 19 – Mar 4	Oregon State, central OR3
	Sow outdoors	Feb 2	Jan 12 – Feb 26	Colorado State4
	Plant for fall	Oct 5 – Oct 19	Sep 21 – Nov 10	Texas A&M (E-502)5
	Plant for fall	Aug 24 – Sep 7	Aug 10 – Sep 29	Texas A&M (E-502)5
Peas	Start indoors	Dec 8	Nov 17 – Jan 1	Oregon State, central OR3
	Transplant outdoors	Jan 5	Dec 15 – Jan 29	Oregon State, central OR3
	Sow outdoors	Jan 5 – Jan 19	Dec 15 – Feb 12	Colorado State4
	Plant for fall	Sep 21 – Nov 30	Sep 7 – Dec 22	Texas A&M (E-502)5
Lettuce	Start indoors	Dec 15	Nov 24 – Jan 8	Oregon State, central OR3
	Transplant outdoors	Jan 19	Dec 29 – Feb 12	Oregon State, central OR3
	Sow outdoors	Jan 5 – Jan 19	Dec 15 – Feb 12	Colorado State4
	Plant for fall	Sep 7 – Oct 5	Aug 24 – Oct 27	Texas A&M (E-502)5
Carrots	Sow outdoors	Jan 19 – Feb 2	Dec 29 – Feb 26	Colorado State4
Carrots	Plant for fall	Sep 7 – Sep 21	Aug 24 – Oct 13	Texas A&M (E-502)5
Onions	Start indoors	Oct 13	Sep 22 – Nov 6	Oregon State, central OR3
	Transplant outdoors	Dec 22	Dec 1 – Jan 15	Oregon State, central OR3
	Sow outdoors	Jan 5 – Jan 19	Dec 15 – Feb 12	Colorado State4
	Plant for fall	Oct 5 – Oct 19	Sep 21 – Nov 10	Texas A&M (E-502)5
Garlic	Plant for fall	Dec 21 – Dec 28	Dec 7 – Jan 19	Wisconsin6
Potatoes	Sow outdoors	Jan 19 – Feb 2	Dec 29 – Feb 26	Colorado State4
Potatoes	Plant for fall	Aug 24 – Sep 7	Aug 10 – Sep 29	Texas A&M (E-502)5
Basil	No frost-relative rule is published; sources give conditions instead (see the crop page).

Sources

PRISM Group, Oregon State University, 2023 USDA Plant Hardiness Zone Map ZIP code data (PHZM 2023), 2023-11-15. Retrieved 2026-11-02.
NOAA National Centers for Environmental Information, U.S. Climate Normals 2020: U.S. Annual/Seasonal Climate Normals (1991-2020), 2021. Retrieved 2026-11-02.
Oregon State University Extension Service, When to start seeds indoors in central Oregon, reviewed 2024. Retrieved 2026-11-02.
Colorado State University Extension, Vegetable Planting Guide (CMG GardenNotes #720), reviewed September 2024. Retrieved 2026-11-02.
Texas AgriLife Extension Service, The Texas A&M System, Texas Home Vegetable Gardening Guide (E-502), 2/09. Retrieved 2026-11-02.
University of Wisconsin–Madison Division of Extension, Wisconsin Horticulture, Garlic, Allium sativum, Rev: 10/2023. Retrieved 2026-11-02.

Zone 9b

When to plant in zone 9b

Sources

Hi, I'm Pip!

First, I check for frost

Then I make your calendar

Where do you garden?