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When to Plant Tomatoes in Otero County, CO

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.

Otero County, Colorado is in USDA Zone 6a. The average last spring frost is April 26 and the first fall frost is October 9, giving you a growing season of approximately 166 days.

At an elevation of 4,145 feet, Otero County receives approximately 14.2 inches of rainfall annually with predominantly loam soil. Summer highs average 90ยฐF, providing good warmth for Tomatoes during the growing season. With low rainfall, drip irrigation is essential for growing Tomatoes successfully. Mulch heavily to conserve soil moisture.

Otero County, CO (Zone 6a) Moderate season
166 days
Last Spring Frost April 26
166 growing days
First Fall Frost October 9

Otero County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (19 days to spare)
Start indoors: Feb 25 Transplant: May 6 🍅 Harvest: Jul 8 – Sep 16
Recommended (50%) ✓ Fits season (19 days to spare)
Start indoors: Mar 1 Transplant: May 10 🍅 Harvest: Jul 12 – Sep 20
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Mar 18 Transplant: May 27 🍅 Harvest: Jul 29 – Oct 7

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
0.4″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,136 gal / 100 sq ft
Drought risk

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

Tomatoes needs ~1,269 GDD — county provides 2,905 GDD Excellent fit

Tomatoes Planting Timeline โ€” Otero County, CO

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors March 1 Mar 1 โ€“ Mar 15
Transplant Outdoors May 10 May 10 โ€“ May 24
Direct Sow May 3 May 3 โ€“ May 24
Harvest July 12 Jul 12 โ€“ Sep 20

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 6a

Growing Season

166 days

Growing Tips for Otero 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 Otero County, CO?

Otero County is in Zone 6a with an average last frost of April 26. Plan your Tomatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Otero County, CO?

Otero County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is April 26 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Otero County gardeners in Zone 6a 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 Otero County, CO. Local conditions may vary. Last updated: April 2026.