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When to Plant Sweet Corn in Hinsdale County, CO

Hinsdale County, Colorado Zone 5a April

Your April gardening checklist

Each item below is timed to Hinsdale County, Colorado's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost June 18
Avg. first frost September 10
Soil temp (4") 24°F
Watering Moderate
Pest pressure Low
Daylight 13 hrs

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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.

Hinsdale County, Colorado is in USDA Zone 5a. The average last spring frost is June 18 and the first fall frost is September 10, giving you a growing season of approximately 84 days.

At an elevation of 6,833 feet, Hinsdale County receives approximately 23.8 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Sweet Corn to ensure they mature before fall.

Hinsdale County, CO (Zone 5a) Very short season
84 days
Last Spring Frost June 18
84 growing days
First Fall Frost September 10
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Hinsdale County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 5 🍅 Harvest: Aug 7 – Sep 18
Recommended (50%) ✗ May not fit
Transplant: Jun 18 🍅 Harvest: Aug 20 – Oct 1
Safe Start (90%) ✗ May not fit
Transplant: Jun 29 🍅 Harvest: Aug 31 – Oct 12

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 Hinsdale County

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

Soil pH

Your soil pH (6.8–8.1) 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 Hinsdale County is excellent for Sweet Corn — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Sweet Corn.

How to Plant Sweet Corn

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

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.2″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 278 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.9" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.8" 0" ❄️ Dormant
May 2.5" 0" ❄️ Dormant
Jun 6.5" 1.4" 5.1" 🚿 Regular watering
Jul 6.5" 2.2" 4.3" 🚿 Regular watering
Aug 6.5" 2.7" 3.8" 🚿 Regular watering
Sep 6.5" 2.2" 4.3" 🚿 Regular watering
Oct 1.9" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Hinsdale 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 ~862 GDD — county provides 966 GDD Good fit

Sweet Corn Planting Timeline — Hinsdale County, CO

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow June 25 Jun 25 – Jul 16
Harvest August 27 Aug 27 – Oct 8

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

84 days in Hinsdale County

Growing Tips for Sweet Corn in Hinsdale County

Direct sow Sweet Corn outdoors after June 18 in Hinsdale County when soil has warmed and frost danger has passed.

Your 84.0-day growing season in Hinsdale County is tight for Sweet Corn (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

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.

Hinsdale County receives only 24" 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 Hinsdale County, CO?

Hinsdale County is in Zone 5a with an average last frost of June 18. Plan your Sweet Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hinsdale County, CO?

Hinsdale County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 18 and first fall frost is September 10.

🌱

Your Hinsdale County Garden Planner — Free

A 24-page printable planner built for Hinsdale County (Zone 5a). 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 Hinsdale 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.