PlantAlong

When to plant peppers in zone 8a

Transplant outdoors around Apr 12. That is 2 weeks after zone 8a's median last frost, Mar 291. Across most of zone 8a that date falls between Apr 3 and Apr 21.

Why a range: zone 8a is defined by winter lows, not frost dates. Its ZIP codes have median last frosts from Mar 20 to Apr 72, 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 8a's frost dates.

Last reviewed
Stations
650
ZIP codes
2,528
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 8a. 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 166 weeks before last frost (Oregon State, central OR)
Transplant outdoors
Apr 12range Apr 3 – Apr 21
First harvest, roughly
Jun 2170 days from transplant1

Five digits. The calendar is computed on your device.

What each source says, applied to zone 8a

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 8a's median frost dates.

Table 1. Peppers rules from every source, at zone 8a's median last frost (Mar 29) and first frost (Nov 6).
SourceWhatRuleZone 8a median
Colorado State1Used aboveTransplant outdoors2 weeks after last frostApr 12
Utah State3Transplant outdoors2 weeks after last frostApr 12
Oregon State, central OR4Transplant outdoors2 weeks after last frostApr 12
Oregon State, central OR4Used aboveStart indoors6 weeks before last frostFeb 16
Texas A&M (E-502)5Transplant outdoors1-8 weeks after last frostApr 5 – May 24
Texas A&M (E-502)5Plant for fall12-16 weeks before first frostJul 17 – Aug 14

Frost across zone 8a

  1. Last spring frostmedian Mar 29
  2. First fall frostmedian Nov 6
  • Frost-free season (median)
Figure 2. Frost dates across zone 8a, from 650 NOAA stations matched to 2,528 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.