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When to Plant Peppers in King County, WA

Sweet peppers are warm-season crops producing fruits in a rainbow of colors. They turn from green to red, yellow, or orange as they ripen, increasing in sweetness.

King County, Washington is in USDA Zone 8b. The average last spring frost is April 7 and the first fall frost is October 30, giving you a growing season of approximately 206 days.

At an elevation of 258 feet, King County receives approximately 37.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Peppers during the growing season.

King County, WA (Zone 8b) Long season
206 days
Last Spring Frost April 7
206 growing days
First Fall Frost October 30

King County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (57 days to spare)
Start indoors: Jan 20 Transplant: Apr 7 🍅 Harvest: Jun 9 – Aug 18
Recommended (50%) ✓ Fits season (59 days to spare)
Start indoors: Feb 3 Transplant: Apr 21 🍅 Harvest: Jun 23 – Sep 1
Safe Start (90%) ✓ Fits season (38 days to spare)
Start indoors: Mar 18 Transplant: Jun 3 🍅 Harvest: Aug 5 – Oct 14

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 428 gal / 100 sq ft
Peppers needs ~1,256 GDD — county provides 3,450 GDD Excellent fit

Peppers Planting Timeline โ€” King County, WA

Peppers Planting Calendar

Activity When Date Range
Start Indoors February 3 Feb 3 โ€“ Feb 17
Transplant Outdoors April 21 Apr 21 โ€“ May 5
Direct Sow April 14 Apr 14 โ€“ May 5
Harvest June 23 Jun 23 โ€“ Sep 1

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March โ€”
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 8b

Growing Season

206 days

Growing Tips for King County

Start seeds indoors 8-10 weeks before last frost. Transplant when nighttime temperatures stay above 55F. Avoid high-nitrogen fertilizers which promote leaves over fruit.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
  • Kohlrabi

Level Up Your Garden

๐ŸŒพ Save Your Own Peppers Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Remove seeds from fully ripe (red/orange) fruit.
Storage Store airtight; viable 4 years at 35ยฐF, under 50% humidity.

Isolate 300 ft for purity. Hot and sweet peppers can cross-pollinate.

Frequently Asked Questions

When should I plant Peppers in King County, WA?

King County is in Zone 8b with an average last frost of April 7. Plan your Peppers planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is King County, WA?

King County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 7 and first fall frost is October 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help King County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for King County, WA. Local conditions may vary. Last updated: April 2026.