PlantAlong

When to plant peppers in zone 8b

Transplant outdoors around Mar 31. That is 2 weeks after zone 8b's median last frost, Mar 171. Across most of zone 8b that date falls between Mar 20 and Apr 15.

Why a range: zone 8b is defined by winter lows, not frost dates. Its ZIP codes have median last frosts from Mar 6 to Apr 12, so a single zone date can be weeks off for you. The rule comes from Colorado State University Extension, written for CO and applied here to zone 8b's frost dates.

Last reviewed
Stations
652
ZIP codes
2,535
Photo: Yan Krukau / Pexels
These dates use the typical last frost for the whole zone. Your ZIP code gives a closer answer.
  1. Start indoorsOregon State, central OR
  2. Transplant outdoorsColorado State
  • 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 1. Peppers in zone 8b. Dark bars: at the zone's median frost dates. Pale bars: across most of the zone's ZIP codes. Hatched blue: where the zone's last and first frosts fall.
Start seeds indoors
Feb 46 weeks before last frost (Oregon State, central OR)
Transplant outdoors
Mar 31range Mar 20 – Apr 15
First harvest, roughly
Jun 970 days from transplant1

Five digits. The calendar is computed on your device.

What each source says, applied to zone 8b

The same frost dates give different answers depending on whose rule you follow. These are all the published rules we hold for peppers, worked out at zone 8b's median frost dates.

Table 1. Peppers rules from every source, at zone 8b's median last frost (Mar 17) and first frost (Nov 13).
SourceWhatRuleZone 8b median
Colorado State1Used aboveTransplant outdoors2 weeks after last frostMar 31
Utah State3Transplant outdoors2 weeks after last frostMar 31
Oregon State, central OR4Transplant outdoors2 weeks after last frostMar 31
Oregon State, central OR4Used aboveStart indoors6 weeks before last frostFeb 4
Texas A&M (E-502)5Transplant outdoors1-8 weeks after last frostMar 24 – May 12
Texas A&M (E-502)5Plant for fall12-16 weeks before first frostJul 24 – Aug 21

Frost across zone 8b

  1. Last spring frostmedian Mar 17
  2. First fall frostmedian Nov 13
  • Frost-free season (median)
Figure 2. Frost dates across zone 8b, from 652 NOAA stations matched to 2,535 ZIP codes.

Sources

  1. Colorado State University Extension, Vegetable Planting Guide (CMG GardenNotes #720), reviewed September 2024. Retrieved 2026-11-02.
  2. NOAA National Centers for Environmental Information, U.S. Climate Normals 2020: U.S. Annual/Seasonal Climate Normals (1991-2020), 2021. Retrieved 2026-11-02.
  3. Utah State University Extension, Suggested Vegetable Planting Dates for Utah, January 2018; revised May 2025. Retrieved 2026-11-02.
  4. Oregon State University Extension Service, When to start seeds indoors in central Oregon, reviewed 2024. Retrieved 2026-11-02.
  5. Texas AgriLife Extension Service, The Texas A&M System, Texas Home Vegetable Gardening Guide (E-502), 2/09. Retrieved 2026-11-02.