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When to Plant Tomatoes in Grays Harbor County, WA

Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.

Grays Harbor County, Washington is in USDA Zone 8a. The average last spring frost is April 27 and the first fall frost is October 23, giving you a growing season of approximately 179 days.

At an elevation of 65 feet, Grays Harbor County receives approximately 39.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Tomatoes during the growing season.

Grays Harbor County, WA (Zone 8a) Moderate season
179 days
Last Spring Frost April 27
179 growing days
First Fall Frost October 23

Grays Harbor County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (33 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jun 30 – Sep 8
Recommended (50%) ✓ Fits season (32 days to spare)
Start indoors: Mar 9 Transplant: May 11 🍅 Harvest: Jul 13 – Sep 21
Safe Start (90%) ✓ Fits season (46 days to spare)
Start indoors: Mar 24 Transplant: May 26 🍅 Harvest: Jul 28 – Oct 6

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
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 120 gal / 100 sq ft
Tomatoes needs ~1,160 GDD — county provides 2,864 GDD Excellent fit

Tomatoes Planting Timeline โ€” Grays Harbor County, WA

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 โ€“ Mar 23
Transplant Outdoors May 11 May 11 โ€“ May 25
Direct Sow May 4 May 4 โ€“ May 25
Harvest July 13 Jul 13 โ€“ Sep 21

Plant 0.5" deep ยท 24" apart ยท Rows 36" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April โ€”
May Transplant Outdoors Direct Sow
June โ€”
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€“85 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 8a

Growing Season

179 days

Growing Tips for Grays Harbor County

Start seeds indoors 6-8 weeks before last frost. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Level Up Your Garden

๐ŸŒพ Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35ยฐF, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in Grays Harbor County, WA?

Grays Harbor County is in Zone 8a with an average last frost of April 27. Plan your Tomatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Grays Harbor County, WA?

Grays Harbor County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 27 and first fall frost is October 23.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Grays Harbor County gardeners in Zone 8a 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 Grays Harbor County, WA. Local conditions may vary. Last updated: April 2026.