Blog

When to Plant Sunflower in Stark County, ND

Stark County, North Dakota Zone 4b May

What to do in May

May is a pivotal month for Stark County, North Dakota gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 14
Avg. first frost September 23
Soil temp (4") 52°F
Watering High
Pest pressure Low
Daylight 14.8 hrs
  1. Sow sunflower where they'll grow

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

A few tasks this May that'll pay off in June
  • Transplants going out: sunflower

Instant PDF download. No spam, unsubscribe any time.

Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

Stark County, North Dakota is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is September 23, giving you a growing season of approximately 132 days.

At an elevation of 1,040 feet, Stark County receives approximately 23.4 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Sunflower to ensure they mature before fall.

Stark County, ND (Zone 4b) Short season
132 days
Last Spring Frost May 14
132 growing days
First Fall Frost September 23
Share this guide:

Stark County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 9 Transplant: Jun 1 🍅 Harvest: Aug 10 – Sep 28
Recommended (50%) ✗ May not fit
Start indoors: Mar 12 Transplant: Jun 4 🍅 Harvest: Aug 13 – Oct 1
Safe Start (90%) ✗ May not fit
Start indoors: Mar 28 Transplant: Jun 20 🍅 Harvest: Aug 29 – Oct 17

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Stark County

How your county's soil matches Sunflower's growing requirements.

Soil pH

Your soil pH (6.6–7.5) is within Sunflower's preferred range (6.0–7.5).

Soil Texture

The loam soil in Stark County is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.6%). Annual compost additions will help Sunflower.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
30"
Between Rows

Succession Planting Sunflower

2
successive plantings in your 132-day season

Sow every 8 weeks. Last sowing by Jun 15 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Sunflower

Sunflower needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Sunflower Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 2.2" 2.3" 0" ✅ Rainfall sufficient
Jun 2.2" 1.8" 0.4" 💧 Light watering
Jul 2.2" 2" 0.2" 💧 Light watering
Aug 2.2" 2.7" 0" ✅ Rainfall sufficient
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.8" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Stark County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sunflower Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Sunflower needs ~978 GDD — county provides 1,518 GDD Excellent fit

Sunflower Planting Timeline — Stark County, ND

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors June 4 Jun 4 – Jun 18
Direct Sow May 28 May 28 – Jun 18
Harvest August 13 Aug 13 – Oct 1

Plant 1" deep · 18" apart · Rows 30" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Direct Sow
June Transplant Outdoors Direct Sow
July
August Harvest
September Harvest
October Harvest
November
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

132 days in Stark County

Growing Tips for Sunflower in Stark County

Direct sow Sunflower outdoors after May 14 in Stark County when soil has warmed and frost danger has passed.

Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Stark County receives only 23" of rain annually. Sunflower needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Stark County, ND?

Stark County is in Zone 4b with an average last frost of May 14. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stark County, ND?

Stark County, North Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is September 23.

🌱

Your Stark County Garden Planner — Free

A 24-page printable planner built for Stark County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Stark County, ND. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.