Zone 4 · Fruit Growing Guide

When to Plant Sunflower
in Zone 4

One of the most cheerful crops in the garden. Edible seeds and cut flowers. Direct sow only — sunflowers dislike transplanting. Great for attracting pollinators and beneficial insects.

Plant outdoors
May 20 – Jun 10
Start indoors
Direct sow
Last Frost
~May 1
Days to harvest
70–100 days
Difficulty
Easy
Wrong season — Zone 4
Harvest window: Aug – Sep

Planting Calendar

In Zone 4, Sunflower should be planted outdoors May 20 – Jun 10, after the average last frost date of approximately May 1.

Direct sow. Succession plant 3 weeks apart for extended bloom.

Care Guide

Sunlight
Full sun · 6–8 hrs/day
Watering
Low
Spacing
12–24 inches
Soil
Well-draining, moderate fertility
Days to maturity
70–100 days
Soil pH
6.0–7.5
plant tip · Zone 4

Direct sow. Succession plant 3 weeks apart for extended bloom.

Feeding Schedule

How often
monthly
Feed type
balanced then high potassium
Key timing
switch to high-potassium at bud formation

Feed balanced fertilizer monthly. Switch to low-nitrogen, high-potassium feed when buds form for better head development.

Succession Planting

Sow every 2 weeks

Sow every 2 weeks from last frost through midsummer. Succession gives you a long season of blooms rather than all flowers opening at once.

Companion Planting for Sunflower

What you plant next to sunflower makes a real difference — some plants actively help, others compete or attract pests.

Grows well with
  • Cucumbers
  • Corn
  • Squash
  • Beans
Keep away from
  • Potatoes
  • Fennel

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Common questions

In Zone 4, direct sow sunflower outdoors May 20 – Jun 10 after your last frost date of approximately May 1. Direct sow. Succession plant 3 weeks apart for extended bloom.
Zone 4 has an average last spring frost of approximately May 1 and a first fall frost around Oct 1. These dates vary by specific location — use your ZIP code in the plant app for precision based on the nearest NOAA weather station.
Good companion crops for sunflower include Cucumbers, Corn, Squash, Beans. Avoid planting near Potatoes, Fennel, which can compete for nutrients or attract pests.
Sunflower typically takes 70–100 days from transplant or direct sow to harvest in Zone 4. Expected harvest window: Aug – Sep.

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Sunflower in other zones
Crop Guides