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When to Plant Tomatillo in Mineral County, CO

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

Mineral County, Colorado is in USDA Zone 4a. The average last spring frost is June 10 and the first fall frost is September 13, giving you a growing season of approximately 95 days.

At an elevation of 7,809 feet, Mineral County receives approximately 12.8 inches of rainfall annually with predominantly loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Tomatillo to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Tomatillo successfully. Mulch heavily to conserve soil moisture.

Mineral County, CO (Zone 4a) Very short season
95 days
Last Spring Frost June 10
95 growing days
First Fall Frost September 13

Mineral County Soil Profile

Soil Type

Loam

Soil pH

6.8-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 27 Transplant: Jun 19 🍅 Harvest: Aug 21 – Oct 30
Recommended (50%) ✗ May not fit
Start indoors: Apr 8 Transplant: Jul 1 🍅 Harvest: Sep 2 – Nov 11
Safe Start (90%) ✗ May not fit
Start indoors: Apr 24 Transplant: Jul 17 🍅 Harvest: Sep 18 – Nov 27

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
0.6″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 745 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Tomatillo needs ~725 GDD — county provides 950 GDD Excellent fit

Tomatillo Planting Timeline โ€” Mineral County, CO

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 โ€“ Apr 22
Transplant Outdoors July 1 Jul 1 โ€“ Jul 15
Direct Sow June 24 Jun 24 โ€“ Jul 15
Harvest September 2 Sep 2 โ€“ Nov 11

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors
May โ€”
June Direct Sow
July Transplant Outdoors Direct Sow
August โ€”
September Harvest
October Harvest
November Harvest
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 4a

Growing Season

95 days

Growing Tips for Mineral 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 Mineral County, CO?

Mineral County is in Zone 4a with an average last frost of June 10. Plan your Tomatillo planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Mineral County, CO?

Mineral County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 10 and first fall frost is September 13.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Mineral County gardeners in Zone 4a 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 Mineral County, CO. Local conditions may vary. Last updated: April 2026.