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When to plant Sunflower in Haskell County, KS

Sunflower planted in Haskell County between April 18 and May 9 matures in 70–100 days — well before the October 18 first frost.

When to Plant Sunflower in Haskell County, KS

Haskell County, Kansas Zone 6b June

Your June planting checklist for Haskell County, Kansas

Here's what deserves your attention in Haskell County, Kansas this month. Everything below is tailored to Zone 6b and timed around your local frost dates.

Avg. last frost April 18
Avg. first frost October 18
Soil temp (4") 74°F
Watering High
Pest pressure High
Daylight 14.6 hrs
Before July arrives, get these ready
  • First harvests: sunflower

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Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.

Haskell County, Kansas is in USDA Zone 6b. The average last spring frost is April 18 and the first fall frost is October 18, giving you a growing season of approximately 183 days.

At an elevation of 824 feet, Haskell County receives approximately 24.4 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Sunflower during the growing season.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Haskell County, KS (Zone 6b) Moderate season
183 days
Last Spring Frost April 18
183 growing days
First Fall Frost October 18

Haskell County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.4

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✓ Fits season (8 days to spare)
Start indoors: Mar 24 Transplant: Apr 14 🌸 Bloom: Jul 7 – Oct 6
Recommended (50%) ✓ Fits season (8 days to spare)
Start indoors: Mar 28 Transplant: Apr 18 🌸 Bloom: Jul 11 – Oct 10
Safe Start (90%) ✓ Fits season (9 days to spare)
Start indoors: Apr 12 Transplant: May 3 🌸 Bloom: Jul 26 – Oct 25

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 Haskell County

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

Soil pH

Your soil pH (6.4–7.4) is within Sunflower's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Sunflower will thrive.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Sunflower

3
successive plantings in your 183-day season

Sow every 8 weeks. Last sowing by Jul 10 to harvest before frost.

Sunflower Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/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 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.2" 2.5" 0" ✅ Rainfall sufficient
May 2.2" 2.8" 0" ✅ Rainfall sufficient
Jun 2.2" 1.6" 0.6" 💧 Light watering
Jul 2.2" 2.2" 0" ✅ Rainfall sufficient
Aug 2.2" 2.3" 0" ✅ Rainfall sufficient
Sep 2.2" 2.2" 0" ✅ Rainfall sufficient
Oct 2.2" 2.1" 0.1" 💧 Light watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Haskell 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 ~1,169 GDD — county provides 2,516 GDD Excellent fit

Sunflower Planting Timeline — Haskell County, KS

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors April 18 Apr 18 – May 2
Direct Sow April 18 Apr 18 – May 9
Bloom July 11 Jul 11 – Oct 10

Plant 1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Bloom
August Bloom
September Bloom
October Bloom
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: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

183 days in Haskell County

Growing Tips for Sunflower in Haskell County

Direct sow Sunflower outdoors after April 18 in Haskell 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.

Haskell County receives only 24" of rain annually. Sunflower needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct-sow 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Pole_beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Haskell County, KS?

Haskell County is in Zone 6b with an average last frost of April 18. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Haskell County, KS?

Haskell County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 18 and first fall frost is October 18.

When should I plant Sunflower in Haskell County, KS?

In Haskell County, KS, plant Sunflower after the last frost (around April 18) and before the first frost (around October 18). Best results when soil holds above 50°F.

What growing zone is Haskell County, KS for Sunflower?

Haskell County sits in USDA Zone 6b. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.

Can Sunflower grow in Haskell County's climate?

Yes — Sunflower grows well in Haskell County's temperate climate. Haskell County averages a 183-day frost-free season, with last frost around April 18 and first frost around October 18.

🌱

Your Haskell County Garden Planner — Free

A 22-page printable planner built for Haskell County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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

Sources & credits

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