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When to Plant Corn in Collin County, TX

Collin County, Texas Zone 8b May

Your May game plan for Collin County, Texas

Your garden in Collin County, Texas is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost March 10
Avg. first frost November 20
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. It's harvest week for corn

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

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.

Collin County, Texas is in USDA Zone 8b. The average last spring frost is March 10 and the first fall frost is November 20, giving you a growing season of approximately 255 days.

At an elevation of 103 feet, Collin County receives approximately 65.2 inches of rainfall annually with predominantly clay soil. Summer highs average 94°F, providing good warmth for Corn during the growing season. Clay soil retains moisture well for Corn, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Corn root diseases.

Collin County, TX (Zone 8b) Long season
255 days
Last Spring Frost March 10
255 growing days
First Fall Frost November 20

Collin County Soil Profile

Soil Type

Clay

Soil pH

7.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (135 days to spare)
Transplant: Mar 2 🍅 Harvest: May 4 – Jun 29
Recommended (50%) ✓ Fits season (136 days to spare)
Transplant: Mar 10 🍅 Harvest: May 12 – Jul 7
Safe Start (90%) ✓ Fits season (121 days to spare)
Transplant: Apr 11 🍅 Harvest: Jun 13 – Aug 8

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 Collin County

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

Soil pH

Your soil pH (7.3–7.8) is more alkaline than Corn prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (43% clay) in Collin County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Corn.

How to Plant Corn

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

Succession Planting Corn

5
successive plantings in your 255-day season

Sow every 6.9 weeks. Last sowing by Aug 12 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.1″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 1,160 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.8" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 6.5" 4.3" 2.2" 💧 Light watering
Apr 6.5" 6.9" 0" ✅ Rainfall sufficient
May 6.5" 10.2" 0" ✅ Rainfall sufficient
Jun 6.5" 9.9" 0" ✅ Rainfall sufficient
Jul 6.5" 7.3" 0" ✅ Rainfall sufficient
Aug 6.5" 8.4" 0" ✅ Rainfall sufficient
Sep 6.5" 6.5" 0" ✅ Rainfall sufficient
Oct 6.5" 3.9" 2.6" 💧 Light watering
Nov 6.5" 2.2" 4.3" 🚿 Regular watering
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Collin 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 ~1,640 GDD — county provides 5,227 GDD Excellent fit

Corn Planting Timeline — Collin County, TX

Corn Planting Calendar

Activity When Date Range
Direct Sow March 17 Mar 17 – Apr 7
Harvest May 19 May 19 – Jul 14

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8b

📆 Growing Season

255 days in Collin County

Growing Tips for Corn in Collin County

Direct sow Corn outdoors after March 10 in Collin County when soil has warmed and frost danger has passed.

With Collin County's clay soil (43% clay), work in 3-4 inches of compost before planting Corn. Avoid tilling when soil is wet to prevent compaction.

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 Collin County, TX?

Collin County is in Zone 8b with an average last frost of March 10. Plan your Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Collin County, TX?

Collin County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 10 and first fall frost is November 20.

🌱

Your Collin County Garden Planner — Free

A 24-page printable planner built for Collin County (Zone 8b). 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 Collin County, TX. 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.