PlantAlong

When to plant beans in zone 7b

Transplant outdoors around Apr 12. That is 1 weeks after zone 7b's median last frost, Apr 51. Across most of zone 7b that date falls between Apr 6 and Apr 24.

Why a range: zone 7b is defined by winter lows, not frost dates. Its ZIP codes have median last frosts from Mar 30 to Apr 172, so a single zone date can be weeks off for you. The rule comes from Oregon State University Extension Service.

Last reviewed
Stations
639
ZIP codes
2,958
Photo: Gobral / 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 outdoorsOregon State, central OR
  3. Sow 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. Beans in zone 7b. 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
Mar 153 weeks before last frost (Oregon State, central OR)
Transplant outdoors
Apr 12range Apr 6 – Apr 24

Five digits. The calendar is computed on your device.

What each source says, applied to zone 7b

The same frost dates give different answers depending on whose rule you follow. These are all the published rules we hold for beans, worked out at zone 7b's median frost dates.

Table 1. Beans rules from every source, at zone 7b's median last frost (Apr 5) and first frost (Nov 1).
SourceWhatRuleZone 7b median
Colorado State3Used aboveSow outdoorsOn the last frostApr 5
Utah State4Sow outdoorsOn the last frostApr 5
Oregon State, central OR1Used aboveTransplant outdoors1 weeks after last frostApr 12
Oregon State, central OR1Used aboveStart indoors3 weeks before last frostMar 15
Texas A&M (E-502)5Sow outdoors1-4 weeks after last frostApr 12 – May 3
Texas A&M (E-502)5Plant for fall8-10 weeks before first frostAug 23 – Sep 6
Texas A&M (E-502)5Plant for fall14-16 weeks before first frostJul 12 – Jul 26

Frost across zone 7b

  1. Last spring frostmedian Apr 5
  2. First fall frostmedian Nov 1
  • Frost-free season (median)
Figure 2. Frost dates across zone 7b, from 639 NOAA stations matched to 2,958 ZIP codes.

Sources

  1. Oregon State University Extension Service, When to start seeds indoors in central Oregon, reviewed 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. Colorado State University Extension, Vegetable Planting Guide (CMG GardenNotes #720), reviewed September 2024. Retrieved 2026-11-02.
  4. Utah State University Extension, Suggested Vegetable Planting Dates for Utah, January 2018; revised May 2025. 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.