When should I plant Sunflower in Zone 9b?

Start Sunflower seeds indoors around Feb 17. Transplant outdoors after Mar 17. Expect first harvest around May 21.

What is the last frost date for Zone 9b?

The average last spring frost date for Zone 9b is Mar 10. The first fall frost averages Nov 15, giving a 250-day growing season.

Can I grow Sunflower in Zone 9b?

Yes. Sunflower needs 90 days to harvest. Zone 9b has a 250-day growing season, which is sufficient. You can plant up to 11 successions.

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🌻 Growing Sunflower in Zone 9b

Zone 9b has warm winters and an extended growing season — excellent for heat-loving crops like Sunflower. Last frost: Mar 10. First frost: Nov 15.

Planting Calendar

Indoor

Outdoor

Harvest

Feb 17Nov 15

Season: Mar 10 – Nov 15 (250 days) · Succession: plant every 2 weeks (up to 11x)

Zone9b

Last FrostMar 10

First FrostNov 15

Season Length250 days

Days to Harvest90

SunFull Sun

Frost ToleranceNone

Spacing1/sqft (12" apart)

When to Plant Sunflower in Zone 9b

Start Seeds Indoors: Feb 17

Start Sunflower seeds indoors around Feb 17 (3 weeks before last frost). Optimal germination temperature: 75°F. Germinates in 7–14 days.

Transplant Outdoors: Mar 17

Transplant Sunflower seedlings outdoors after Mar 17. Wait until soil temperature reaches 55°F. Space plants at 1/sqft (12" apart). Harden off plants for a week before moving outside.

Harvest: May 21

First harvest approximately May 21 (~65 days from transplant). Continue harvesting until first frost (Nov 15).

Companion Planting

✅ Cucumbers✅ Squash ✅ Corn✅ Beans

❌ Potatoes

Sunflower in Other Zones

1a 1b 2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b 11a 11b 12a 12b 13a 13b

Plan Your Sunflower Garden

Track Sunflower from seed to harvest with personalized frost dates, watering recommendations, and companion planting visualization.

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