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When to Plant Sweet Corn in Otero County, CO

Otero County, Colorado Zone 6a April

Otero County, Colorado gardeners: here's your April plan

April rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Otero County, Colorado.

Avg. last frost April 26
Avg. first frost October 9
Soil temp (4") 40°F
Watering High
Pest pressure Low
Daylight 13 hrs
Looking ahead to May
  • Direct-sowing: sweet corn

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Sweet corn is bred for high sugar content in its kernels, which convert to starch rapidly after harvest. Modern supersweet varieties hold their sweetness longer.

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 90°F, providing good warmth for Sweet Corn during the growing season. With low rainfall, drip irrigation is essential for growing Sweet Corn 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 (61 days to spare)
Transplant: Apr 22 🍅 Harvest: Jun 24 – Aug 5
Recommended (50%) ✓ Fits season (61 days to spare)
Transplant: Apr 26 🍅 Harvest: Jun 28 – Aug 9
Safe Start (90%) ✓ Fits season (59 days to spare)
Transplant: May 13 🍅 Harvest: Jul 15 – Aug 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.

Soil Compatibility in Otero County

How your county's soil matches Sweet Corn's growing requirements.

Soil pH

Your soil pH (6.4–8.1) is more alkaline than Sweet Corn prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Otero County is excellent for Sweet Corn — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Sweet Corn.

How to Plant Sweet Corn

1"
Planting Depth
12"
Between Plants
36"
Between Rows

Succession Planting Sweet Corn

3
successive plantings in your 166-day season

Sow every 6.9 weeks. Last sowing by Jul 11 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.4″/week
You supply
1.4″/week
Watering frequency 2-3 times/week
Season total 2,022 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Sweet Corn

Sweet Corn needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Sweet Corn Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 6.5" 1.4" 5.1" 🚿 Regular watering
May 6.5" 1.5" 5" 🚿 Regular watering
Jun 6.5" 1.1" 5.4" 🚿 Regular watering
Jul 6.5" 1.5" 5" 🚿 Regular watering
Aug 6.5" 1.3" 5.2" 🚿 Regular watering
Sep 6.5" 1.1" 5.4" 🚿 Regular watering
Oct 6.5" 1.2" 5.3" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Otero County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sweet Corn Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Sweet Corn needs ~1,312 GDD — county provides 2,905 GDD Excellent fit

Sweet Corn Planting Timeline — Otero County, CO

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow May 3 May 3 – May 24
Harvest July 5 Jul 5 – Aug 16

Plant 1" deep · 12" apart · Rows 36" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Direct Sow
June
July Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

166 days in Otero County

Growing Tips for Sweet Corn in Otero County

Direct sow Sweet Corn outdoors after April 26 in Otero County when soil has warmed and frost danger has passed.

Common pests for Sweet Corn in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.

Otero County receives only 14" of rain annually. Sweet Corn needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant in blocks of at least 4 rows for wind pollination. Direct sow after soil is warm. Isolate supersweet varieties from other corn types to prevent cross-pollination.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Corn in Otero County, CO?

Otero County is in Zone 6a with an average last frost of April 26. Plan your Sweet Corn planting based on this frost date — 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.

🌱

Your Otero County Garden Planner — Free

A 24-page printable planner built for Otero County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Otero County, CO. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.