When should I plant Sunflower in Zone 1b?

Start Sunflower seeds indoors around May 4. Transplant outdoors after Jun 1. Expect first harvest around Aug 5.

What is the last frost date for Zone 1b?

The average last spring frost date for Zone 1b is May 25. The first fall frost averages Aug 28, giving a 95-day growing season.

Can I grow Sunflower in Zone 1b?

Yes. Sunflower needs 90 days to harvest. Zone 1b has a 95-day growing season, which is sufficient.

🌻

🌻 Growing Sunflower in Zone 1b

Zone 1b has harsh winters and a short growing season. Start Sunflower early indoors to maximize your harvest window. Last frost: May 25. First frost: Aug 28.

Planting Calendar

Indoor

Outdoor

Harvest

May 4Aug 28

Season: May 25 – Aug 28 (95 days)

Zone1b

Last FrostMay 25

First FrostAug 28

Season Length95 days

Days to Harvest90

SunFull Sun

Frost ToleranceNone

Spacing1/sqft (12" apart)

When to Plant Sunflower in Zone 1b

Start Seeds Indoors: May 4

Start Sunflower seeds indoors around May 4 (3 weeks before last frost). Optimal germination temperature: 75°F. Germinates in 7–14 days.

Transplant Outdoors: Jun 1

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

Harvest: Aug 5

First harvest approximately Aug 5 (~65 days from transplant). Continue harvesting until first frost (Aug 28).

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.

Start Free Sunflower Growing Guide