When to Plant Sunflower in USDA Zone 9b
Your June planting checklist for Zone 9b
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Zone 9b.
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Start harvesting sunflower
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Before July arrives, get these ready
- 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 9b, the average last spring frost is around January 25 and the first fall frost is around December 20, giving you a growing season of approximately 329 days.
Sunflower Planting Timeline — Zone 9b
Where Is USDA Zone 9b?
The map below highlights the states that contain Zone 9b. Click any state to see the Sunflower planting schedule for that location.
Sunflower Planting Calendar — Zone 9b
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 4 | Jan 4 – Jan 18 |
| Transplant Outdoors | December 28 | Dec 28 – Jan 11 |
| Direct Sow | December 28 | Dec 28 – Jan 18 |
| Bloom | March 22 | Mar 22 – Sep 6 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Transplant Outdoors Direct Sow |
| February | — |
| March | Bloom |
| April | Bloom |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | Transplant Outdoors Direct Sow |
Free Zone 9b Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 9b 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
25°F to 30°F average annual minimum
Growing Season
329 days (Zone 9b average)
Planting Specifications
| Planting Depth | 1 inches |
| Plant Spacing | 18 inches apart |
| Row Spacing | 24 inches between rows |
Succession Planting Sunflower in Zone 9b
Sow every 8 weeks for continuous harvest throughout the season.
Growing Tips for Sunflower in Zone 9b
Zone 9b offers a long growing season (~329 days). You can plant Sunflower earlier and may get multiple harvests.
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
The pairings that make vegetables, herbs, and flowers grow better — and the ones that quietly wreck a bed.
- Proven pairings for 200+ vegetables, herbs, flowers, and fruits
- Full seed-starting + planting schedule with timing and spacing
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Saving Sunflower Seeds
Recommended for Your Garden
Reduce heat stress and sun scorch in hot climates with UV-stabilized shade cloth.
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
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 9b?
In Zone 9b, plan your Sunflower planting around the average last frost date of January 25. Start seeds indoors around January 4. Direct sow outdoors around December 28. Transplant seedlings around December 28.
Can Sunflower grow in Zone 9b?
Yes, Sunflower can grow well in Zone 9b, hardy in USDA zones 2a through 11b. Zone 9b has a growing season of approximately 329 days, which is sufficient for Sunflower (70-100 days to maturity).
When can I harvest Sunflower in Zone 9b?
In Zone 9b, expect to harvest Sunflower from March 22 – September 6. Sunflower takes 70-100 days from planting to harvest.
What is the last frost date for Zone 9b?
The average last spring frost in Zone 9b is around January 25, and the first fall frost is around December 20. This gives a growing season of approximately 329 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 9b Garden Planner — Free
A 22-page printable planner tailored to Zone 9b. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.