Blog

When to Plant Tomatillo in Gunnison 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.

Gunnison County, Colorado is in USDA Zone 4a. The average last spring frost is June 12 and the first fall frost is September 10, giving you a growing season of approximately 90 days.

At an elevation of 7,435 feet, Gunnison County receives approximately 17.9 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, 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.

Gunnison County, CO (Zone 4a) Very short season
90 days
Last Spring Frost June 12
90 growing days
First Fall Frost September 10

Gunnison County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.9

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 10 Transplant: Jul 3 🍅 Harvest: Sep 4 – Nov 13
Safe Start (90%) ✗ May not fit
Start indoors: Apr 23 Transplant: Jul 16 🍅 Harvest: Sep 17 – Nov 26

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 158 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Tomatillo needs ~888 GDD — county provides 1,102 GDD Good fit

Tomatillo Planting Timeline โ€” Gunnison County, CO

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 โ€“ Apr 24
Transplant Outdoors July 3 Jul 3 โ€“ Jul 17
Direct Sow June 26 Jun 26 โ€“ Jul 17
Harvest September 4 Sep 4 โ€“ Nov 13

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

90 days

Growing Tips for Gunnison 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 Gunnison County, CO?

Gunnison County is in Zone 4a with an average last frost of June 12. Plan your Tomatillo planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Gunnison County, CO?

Gunnison County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 12 and first fall frost is September 10.

๐ŸŒฑ

Plan Your Garden with Confidence

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