When to Plant Sunflower in USDA Zone 5a
Your May game plan for Zone 5a
Each item below is timed to Zone 5a's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Get sunflower in the ground
Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.
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Seed sunflower outdoors
Your soil is warming°F — warm enough for these to germinate without babying.
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 5a, the average last spring frost is around April 25 and the first fall frost is around October 8, giving you a growing season of approximately 166 days.
Sunflower Planting Timeline — Zone 5a
Where Is USDA Zone 5a?
The map below highlights the states that contain Zone 5a. Click any state to see the Sunflower planting schedule for that location.
Sunflower Planting Calendar — Zone 5a
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 28 | Feb 28 – Mar 14 |
| Transplant Outdoors | May 9 | May 9 – May 23 |
| Direct Sow | May 2 | May 2 – May 23 |
| Harvest | July 18 | Jul 18 – Sep 5 |
Plant 1" deep · 18" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Free Zone 5a Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 5a with start dates, transplant windows, and harvest times.
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
°F to °F average annual minimum
Growing Season
166 days (Zone average)
Planting Specifications
| Planting Depth | 1 inches |
| Plant Spacing | 18 inches apart |
| Row Spacing | 30 inches between rows |
Succession Planting Sunflower in Zone
Sow every 8 weeks for continuous harvest throughout the season.
Growing Tips for Sunflower in Zone
Zone has a short growing season (~166 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
The Gardener's Encyclopedia to Companion Planting
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- Proven pairings for 200+ vegetables, herbs, flowers, and fruits
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Saving Sunflower Seeds
Recommended for Your Garden
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Keep your garden organized with durable, weather-resistant plant labels.
Related Plants
Sunflower in Other Zones
Sunflower by State
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Frequently Asked Questions
When should I plant Sunflower in Zone 5a?
In Zone 5a, plan your Sunflower planting around the average last frost date of April 25. Start seeds indoors around February 28. Direct sow outdoors around May 2. Transplant seedlings around May 9.
Can Sunflower grow in Zone 5a?
Yes, Sunflower can grow well in Zone 5a, hardy in USDA zones 2a through 11b. Zone 5a has a growing season of approximately 166 days, which is sufficient for Sunflower (70-100 days to maturity).
When can I harvest Sunflower in Zone 5a?
In Zone 5a, expect to harvest Sunflower from July 18 – September 5. Sunflower takes 70-100 days from planting to harvest.
What is the last frost date for Zone 5a?
The average last spring frost in Zone 5a is around April 25, and the first fall frost is around October 8. This gives a growing season of approximately 166 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.
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.