Sunflower illustration 🌻

🌻 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

Frequently Asked Questions

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.

What is the best month to plant Sunflower in Zone 1b?

The best time to start Sunflower in Zone 1b is May. Begin seeds indoors around May 4, then transplant outdoors after the last frost date of May 25.

What companion plants grow well with Sunflower?

Good companion plants for Sunflower include Cucumbers, Squash, Corn, Beans. Avoid planting Sunflower near Potatoes.

How long does Sunflower take to harvest?

Sunflower takes approximately 90 days from planting to harvest. In Zone 1b, expect your first harvest around Aug 5.

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