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When to Plant Sunflower in USDA Zone 2b

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 2b, the average last spring frost is around May 22 and the first fall frost is around September 10, giving you a growing season of approximately 111 days.

Zone 2b Short season
111 days
Last Spring Frost May 22
111 growing days
First Fall Frost September 10

Sunflower Planting Timeline — Zone 2b

Where Is USDA Zone 2b?

The map below highlights the states that contain Zone 2b. 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 2b

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors June 12 Jun 12 – Jun 26
Direct Sow June 5 Jun 5 – Jun 26
Harvest August 21 Aug 21 – Oct 9

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

Month-by-Month Timeline

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

Free Zone 2b Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 2b 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

-45°F to -40°F average annual minimum

Growing Season

111 days (Zone 2b average)

Planting Specifications

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

Growing Tips for Sunflower in Zone 2b

Zone 2b has a short growing season (~111 days). Start Sunflower indoors early and use season-extension techniques like row covers and cold frames.

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

💡
LED Grow Lights $25-60

Full-spectrum LED lights for starting seeds indoors when daylight is limited.

🔥
Seedling Heat Mat $15-35

Warm soil for faster germination of heat-loving crops like tomatoes and peppers.

🪡
Floating Row Covers $12-30

Protect plants from frost, wind, and pests while letting light and water through.

Related Plants

Frequently Asked Questions

When should I plant Sunflower in Zone 2b?

In Zone 2b, plan your Sunflower planting around the average last frost date of May 22. Start seeds indoors around March 20. Direct sow outdoors around June 5. Transplant seedlings around June 12.

Can Sunflower grow in Zone 2b?

Yes, Sunflower can grow well in Zone 2b, hardy in USDA zones 2a through 11b. Zone 2b has a growing season of approximately 111 days, which is sufficient for Sunflower (70-100 days to maturity).

When can I harvest Sunflower in Zone 2b?

In Zone 2b, expect to harvest Sunflower from August 21 – October 9. Sunflower takes 70-100 days from planting to harvest.

What is the last frost date for Zone 2b?

The average last spring frost in Zone 2b is around May 22, and the first fall frost is around September 10. This gives a growing season of approximately 111 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 2b, 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.