When to Plant Sunflower in Alaska

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.

Alaska spans USDA hardiness zones 2a, 2b, 3b, 4a, 4b, 5a, 5b, 6b, 7a, 7b, 8a (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

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Click your county for exact Sunflower planting dates based on your local frost dates.

Hover over a county to see details. Click to view planting guide.

Sunflower Planting Calendar for Alaska

▸ Zone 2a ~94 day growing season · Full guide →

Last frost: May 30 · First frost: September 1 · 94 day season

Activity	When	Date Range
Start Indoors	May 9	May 9 – May 23
Transplant Outdoors	June 13	Jun 13 – Jun 27
Direct Sow	June 13	Jun 13 – Jul 4
Bloom	September 5	Sep 5 – Oct 17

▸ Zone 2b ~111 day growing season · Full guide →

Last frost: May 22 · First frost: September 10 · 111 day season

Activity	When	Date Range
Start Indoors	May 1	May 1 – May 15
Transplant Outdoors	June 5	Jun 5 – Jun 19
Direct Sow	June 5	Jun 5 – Jun 26
Bloom	August 28	Aug 28 – Oct 16

▸ Zone 3b ~135 day growing season · Full guide →

Last frost: May 10 · First frost: September 22 · 135 day season

Activity	When	Date Range
Start Indoors	April 19	Apr 19 – May 3
Transplant Outdoors	May 24	May 24 – Jun 7
Direct Sow	May 24	May 24 – Jun 14
Bloom	August 16	Aug 16 – Oct 11

▸ Zone 4a ~145 day growing season · Full guide →

Last frost: May 6 · First frost: September 28 · 145 day season

Activity	When	Date Range
Start Indoors	April 15	Apr 15 – Apr 29
Transplant Outdoors	May 20	May 20 – Jun 3
Direct Sow	May 20	May 20 – Jun 10
Bloom	August 12	Aug 12 – Oct 7

▸ Zone 4b ~155 day growing season · Full guide →

Last frost: May 1 · First frost: October 3 · 155 day season

Activity	When	Date Range
Start Indoors	April 10	Apr 10 – Apr 24
Transplant Outdoors	May 8	May 8 – May 22
Direct Sow	May 8	May 8 – May 29
Bloom	July 31	Jul 31 – Oct 2

▸ Zone 5a ~166 day growing season · Full guide →

Last frost: April 25 · First frost: October 8 · 166 day season

Activity	When	Date Range
Start Indoors	April 4	Apr 4 – Apr 18
Transplant Outdoors	May 2	May 2 – May 16
Direct Sow	May 2	May 2 – May 23
Bloom	July 25	Jul 25 – Oct 3

▸ Zone 5b ~178 day growing season · Full guide →

Last frost: April 18 · First frost: October 13 · 178 day season

Activity	When	Date Range
Start Indoors	March 28	Mar 28 – Apr 11
Transplant Outdoors	April 25	Apr 25 – May 9
Direct Sow	April 25	Apr 25 – May 16
Bloom	July 18	Jul 18 – Oct 3

▸ Zone 6b ~205 day growing season · Full guide →

Last frost: April 3 · First frost: October 25 · 205 day season

Activity	When	Date Range
Start Indoors	March 13	Mar 13 – Mar 27
Transplant Outdoors	April 3	Apr 3 – Apr 17
Direct Sow	April 3	Apr 3 – Apr 24
Bloom	June 26	Jun 26 – Sep 25

▸ Zone 7a ~221 day growing season · Full guide →

Last frost: March 25 · First frost: November 1 · 221 day season

Activity	When	Date Range
Start Indoors	March 4	Mar 4 – Mar 18
Transplant Outdoors	March 25	Mar 25 – Apr 8
Direct Sow	March 25	Mar 25 – Apr 15
Bloom	June 17	Jun 17 – Sep 23

▸ Zone 7b ~235 day growing season · Full guide →

Last frost: March 18 · First frost: November 8 · 235 day season

Activity	When	Date Range
Start Indoors	February 25	Feb 25 – Mar 11
Transplant Outdoors	March 18	Mar 18 – Apr 1
Direct Sow	March 18	Mar 18 – Apr 8
Bloom	June 10	Jun 10 – Sep 30

▸ Zone 8a ~255 day growing season · Full guide →

Last frost: March 8 · First frost: November 18 · 255 day season

Activity	When	Date Range
Start Indoors	February 15	Feb 15 – Mar 1
Transplant Outdoors	March 1	Mar 1 – Mar 15
Direct Sow	March 1	Mar 1 – Mar 22
Bloom	May 24	May 24 – Sep 27

Growing Tips for Alaska

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.

Sunflower in Other States

Frequently Asked Questions

When should I plant Sunflower in Alaska?

Planting dates for Sunflower in Alaska depend on your USDA zone. Alaska spans zones 2a, 2b, 3b, 4a, 4b, 5a, 5b, 6b, 7a, 7b, 8a. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Alaska for planting?

Alaska contains USDA hardiness zones 2a, 2b, 3b, 4a, 4b, 5a, 5b, 6b, 7a, 7b, 8a. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.

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