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When to Plant Sunflower in Perkins County, SD

Perkins County, South Dakota Zone 4b May

Your May planting checklist for Perkins County, South Dakota

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

Avg. last frost May 12
Avg. first frost October 2
Soil temp (4") 53°F
Watering Moderate
Pest pressure Low
Daylight 14.7 hrs
  1. Put sunflower seeds straight in the ground

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

June prep starts now
  • Transplants going out: sunflower

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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.

Perkins County, South Dakota is in USDA Zone 4b. The average last spring frost is May 12 and the first fall frost is October 2, giving you a growing season of approximately 143 days.

At an elevation of 1,119 feet, Perkins County receives approximately 28.1 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Sunflower to ensure they mature before fall.

Perkins County, SD (Zone 4b) Short season
143 days
Last Spring Frost May 12
143 growing days
First Fall Frost October 2

Perkins County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Start indoors: Mar 3 Transplant: May 26 🍅 Harvest: Aug 4 – Sep 22
Recommended (50%) ✓ Fits season (3 days to spare)
Start indoors: Mar 10 Transplant: Jun 2 🍅 Harvest: Aug 11 – Sep 29
Safe Start (90%) ✓ Fits season (6 days to spare)
Start indoors: Mar 18 Transplant: Jun 10 🍅 Harvest: Aug 19 – Oct 7

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 Perkins County

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

Soil pH

Your soil pH (6.7–7.7) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Sunflower will thrive.

How to Plant Sunflower

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

Succession Planting Sunflower

2
successive plantings in your 143-day season

Sow every 8 weeks. Last sowing by Jun 24 to harvest before frost.

Plant Water Budget

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

Water stress score is 10/10 — 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 2.2" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 2.2" 3.2" 0" ✅ Rainfall sufficient
Jun 2.2" 2.1" 0.1" 💧 Light watering
Jul 2.2" 2.7" 0" ✅ Rainfall sufficient
Aug 2.2" 3.2" 0" ✅ Rainfall sufficient
Sep 2.2" 2.1" 0.1" 💧 Light watering
Oct 2.2" 2.1" 0.1" 💧 Light watering
Nov 1.9" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Perkins 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 ~914 GDD — county provides 1,537 GDD Excellent fit

Sunflower Planting Timeline — Perkins County, SD

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors June 2 Jun 2 – Jun 16
Direct Sow May 26 May 26 – Jun 16
Harvest August 11 Aug 11 – Sep 29

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
November
December

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: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

143 days in Perkins County

Growing Tips for Sunflower in Perkins County

Direct sow Sunflower outdoors after May 12 in Perkins 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.

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 Perkins County, SD?

Perkins County is in Zone 4b with an average last frost of May 12. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Perkins County, SD?

Perkins County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 12 and first fall frost is October 2.

🌱

Your Perkins County Garden Planner — Free

A 24-page printable planner built for Perkins 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 Perkins County, SD. 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.