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When to Plant Tomatillo in Mason County, WA

Tomatillos are a Mexican staple that produces tart, green fruits enclosed in papery husks. They are essential for salsa verde and green sauces.

Mason County, Washington is in USDA Zone 8a. The average last spring frost is April 18 and the first fall frost is October 29, giving you a growing season of approximately 194 days.

At an elevation of 230 feet, Mason County receives approximately 36.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Tomatillo during the growing season.

Mason County, WA (Zone 8a) Moderate season
194 days
Last Spring Frost April 18
194 growing days
First Fall Frost October 29

Mason County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (47 days to spare)
Start indoors: Feb 15 Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 30
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Feb 28 Transplant: May 2 🍅 Harvest: Jul 4 – Sep 12
Safe Start (90%) ✓ Fits season (60 days to spare)
Start indoors: Mar 21 Transplant: May 23 🍅 Harvest: Jul 25 – Oct 3

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 362 gal / 100 sq ft
Tomatillo needs ~997 GDD — county provides 2,667 GDD Excellent fit

Tomatillo Planting Timeline โ€” Mason County, WA

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 โ€“ Mar 14
Transplant Outdoors May 2 May 2 โ€“ May 16
Direct Sow April 25 Apr 25 โ€“ May 16
Harvest July 4 Jul 4 โ€“ Sep 12

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors
April Direct Sow
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

194 days

Growing Tips for Mason County

Start seeds indoors 6-8 weeks before last frost. Plant at least two plants for cross-pollination. Harvest when fruits fill the husk and it begins to split.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
  • Dill

Level Up Your Garden

Frequently Asked Questions

When should I plant Tomatillo in Mason County, WA?

Mason County is in Zone 8a with an average last frost of April 18. Plan your Tomatillo planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Mason County, WA?

Mason County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 18 and first fall frost is October 29.

๐ŸŒฑ

Plan Your Garden with Confidence

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

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