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When to Plant Sunflower in USDA Zone 6a

Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

In Zone 6a, the average last spring frost is around April 10 and the first fall frost is around October 20, giving you a growing season of approximately 193 days.

Zone 6a Moderate season
193 days
Last Spring Frost April 10
193 growing days
First Fall Frost October 20

Sunflower Planting Timeline — Zone 6a

Where Is USDA Zone 6a?

The map below highlights the states that contain Zone 6a. Click any state to see the Sunflower planting schedule for that location.

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

Sunflower Planting Calendar — Zone 6a

Activity When Date Range
Start Indoors February 13 Feb 13 – Feb 27
Transplant Outdoors April 24 Apr 24 – May 8
Direct Sow April 17 Apr 17 – May 8
Harvest July 3 Jul 3 – Aug 21

Plant 1" deep · 18" apart · Rows 30" apart

Month-by-Month Timeline

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

Free Zone 6a Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 6a with start dates, transplant windows, and harvest times.

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Growing Conditions

Sun

Full Sun (6-8+ hours)

💧 Water

Low — drought tolerant

Days to Maturity

70–100 days

Soil pH

6 – 7.5

Zone Temperature Range

-10°F to -5°F average annual minimum

Growing Season

193 days (Zone 6a average)

Planting Specifications

Planting Depth1 inches
Plant Spacing18 inches apart
Row Spacing30 inches between rows

Succession Planting Sunflower in Zone 6a

3
successive plantings in Zone 6a's ~193-day season

Sow every 8 weeks for continuous harvest throughout the season.

Growing Tips for Sunflower in Zone 6a

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Saving Sunflower Seeds

Recommended for Your Garden

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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 Sunflower in Zone 6a?

In Zone 6a, plan your Sunflower planting around the average last frost date of April 10. Start seeds indoors around February 13. Direct sow outdoors around April 17. Transplant seedlings around April 24.

Can Sunflower grow in Zone 6a?

Yes, Sunflower can grow well in Zone 6a, hardy in USDA zones 2a through 11b. Zone 6a has a growing season of approximately 193 days, which is sufficient for Sunflower (70-100 days to maturity).

When can I harvest Sunflower in Zone 6a?

In Zone 6a, expect to harvest Sunflower from July 3 – August 21. Sunflower takes 70-100 days from planting to harvest.

What is the last frost date for Zone 6a?

The average last spring frost in Zone 6a is around April 10, and the first fall frost is around October 20. This gives a growing season of approximately 193 days. These are 50% probability dates — actual frost dates vary year to year.

What should I plant next to Sunflower?

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

🌱

Plan Your Garden with Confidence

Get our free Garden Planner — organize your planting dates for Zone 6a, track your crops, and plan your garden season from seed to harvest.

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Free download. Plan your entire garden season in minutes.

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: April 2026.