When to Plant Sunflower in USDA Zone 6a
This month in Zone 6a
Your garden in Zone 6a is working on a schedule, even when you're not. Here's where you should be this June.
July will be here before you know it — start on
- First harvests: sunflower
Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.
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.
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.
Sunflower Planting Calendar — Zone 6a
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 20 | Mar 20 – Apr 3 |
| Transplant Outdoors | April 17 | Apr 17 – May 1 |
| Direct Sow | April 17 | Apr 17 – May 8 |
| Bloom | July 10 | Jul 10 – Oct 2 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| 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.
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 Depth | 1 inches |
| Plant Spacing | 18 inches apart |
| Row Spacing | 24 inches between rows |
Succession Planting Sunflower in Zone 6a
Sow every 8 weeks for continuous harvest throughout the season.
Growing Tips for Sunflower in Zone 6a
Direct-sow 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.
Companion Planting
Good Companions
Avoid Planting Near
The Gardener's Encyclopedia to Companion Planting
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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 6a?
In Zone 6a, plan your Sunflower planting around the average last frost date of April 10. Start seeds indoors around March 20. Direct sow outdoors around April 17. Transplant seedlings around April 17.
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 10 – October 2. 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 Cucumbers, Squash, Corn, Tomatoes. These companions can help with pest control, pollination, and nutrient sharing.
Your Zone 6a Garden Planner — Free
A 22-page printable planner tailored to Zone 6a. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.