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When to Plant Corn in Adair County, OK

Adair County, Oklahoma Zone 7b May

May in Adair County, Oklahoma — your action list

May is a pivotal month for Adair County, Oklahoma gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 7
Avg. first frost October 27
Soil temp (4") 66°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
Looking ahead to June
  • First harvests: corn

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Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.

Adair County, Oklahoma is in USDA Zone 7b. The average last spring frost is April 7 and the first fall frost is October 27, giving you a growing season of approximately 203 days.

At an elevation of 486 feet, Adair County receives approximately 33.9 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Corn during the growing season.

Adair County, OK (Zone 7b) Long season
203 days
Last Spring Frost April 7
203 growing days
First Fall Frost October 27

Adair County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (90 days to spare)
Transplant: Mar 28 🍅 Harvest: May 30 – Jul 25
Recommended (50%) ✓ Fits season (84 days to spare)
Transplant: Apr 7 🍅 Harvest: Jun 9 – Aug 4
Safe Start (90%) ✓ Fits season (90 days to spare)
Transplant: Apr 25 🍅 Harvest: Jun 27 – Aug 22

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 Adair County

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

Soil pH

Your soil pH (6.7–7.1) overlaps with Corn's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — Corn will thrive.

How to Plant Corn

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

Succession Planting Corn

3
successive plantings in your 203-day season

Sow every 6.9 weeks. Last sowing by Jul 19 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.7″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,443 gal / 100 sq ft

Monthly Watering Guide for Corn

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 Corn Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 6.5" 4.2" 2.3" 💧 Light watering
May 6.5" 4.5" 2" 💧 Light watering
Jun 6.5" 5.5" 1" 💧 Light watering
Jul 6.5" 4.1" 2.4" 💧 Light watering
Aug 6.5" 3.6" 2.9" 💧 Light watering
Sep 6.5" 3.1" 3.4" 🚿 Regular watering
Oct 6.5" 2.4" 4.1" 🚿 Regular watering
Nov 1.2" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

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

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.

Corn needs ~1,580 GDD — county provides 4,009 GDD Excellent fit

Corn Planting Timeline — Adair County, OK

Corn Planting Calendar

Activity When Date Range
Direct Sow April 14 Apr 14 – May 5
Harvest June 16 Jun 16 – Aug 11

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Direct Sow
May Direct Sow
June Harvest
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

60–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

203 days in Adair County

Growing Tips for Corn in Adair County

Direct sow Corn outdoors after April 07 in Adair County when soil has warmed and frost danger has passed.

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

General growing tips

Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Celery

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Corn in Adair County, OK?

Adair County is in Zone 7b with an average last frost of April 7. Plan your Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Adair County, OK?

Adair County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is April 7 and first fall frost is October 27.

🌱

Your Adair County Garden Planner — Free

A 24-page printable planner built for Adair County (Zone 7b). 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 Adair County, OK. Local conditions may vary. Last updated: May 2026.

Sources & credits

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