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When to Plant Corn in USDA Zone 4b

Zone 4b Zone 4b May

What to do in May

Welcome to May in Zone 4b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 11
Avg. first frost October 2
  1. Put corn seeds straight in the ground

    These tolerate cool soil, so you're not gambling by sowing now.

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Corn

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.

In Zone 4b, the average last spring frost is around May 1 and the first fall frost is around October 3, giving you a growing season of approximately 155 days.

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Zone 4b Moderate season
155 days
Last Spring Frost May 1
155 growing days
First Fall Frost October 3

Corn Planting Timeline — Zone 4b

Where Is USDA Zone 4b?

The map below highlights the states that contain Zone 4b. Click any state to see the Corn planting schedule for that location.

Prints a clean, ink-friendly version without maps or navigation.

Corn Planting Calendar — Zone 4b

Activity When Date Range
Direct Sow May 15 May 15 – Jun 5
Harvest July 17 Jul 17 – Sep 11

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

Month-by-Month Timeline

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

Free Zone 4b Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 4b with start dates, transplant windows, and harvest times.

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Growing Conditions

Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · Moderate — regular watering

Days to Maturity

60–100 days

Soil pH

6 – 7

Zone Temperature Range

°F to °F average annual minimum

Growing Season

155 days (Zone average)

Planting Specifications

Planting Depth1 inches
Plant Spacing12 inches apart
Row Spacing36 inches between rows

Succession Planting Corn in Zone

2
successive plantings in Zone 's ~155-day season

Sow every 6.9 weeks for continuous harvest throughout the season.

Growing Tips for Corn in Zone

Zone has a short growing season (~155 days). Start Corn indoors early and use season-extension techniques like row covers and cold frames.

Corn needs approximately 1.5 inches of water per week during active growth. Adjust watering based on your local rainfall and soil drainage.

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
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Saving Corn Seeds

Recommended for Your Garden

🌱
Seed Starting Trays $8-20

Start seeds indoors with reusable cell trays and humidity domes.

🧪
Soil Test Kit $12-25

Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.

🏷️
Garden Plant Markers $6-12

Keep your garden organized with durable, weather-resistant plant labels.

Related Plants

Frequently Asked Questions

When should I plant Corn in Zone 4b?

In Zone 4b, plan your Corn planting around the average last frost date of May 1. Direct sow outdoors around May 15.

Can Corn grow in Zone 4b?

Yes, Corn can grow well in Zone 4b, hardy in USDA zones 3a through 11b. Zone 4b has a growing season of approximately 155 days, which is sufficient for Corn (60-100 days to maturity).

When can I harvest Corn in Zone 4b?

In Zone 4b, expect to harvest Corn from July 17 – September 11. Corn takes 60-100 days from planting to harvest.

What is the last frost date for Zone 4b?

The average last spring frost in Zone 4b is around May 1, and the first fall frost is around October 3. This gives a growing season of approximately 155 days. These are 50% probability dates — actual frost dates vary year to year.

What should I plant next to Corn?

Good companion plants for Corn include Squash Summer, Green Beans, Peas, Cucumber. These companions can help with pest control, pollination, and nutrient sharing.

🌱

Your Free Printable Garden Planner

A 24-page printable planner tailored to your zone. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — 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.