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When to Plant Sunflower in Beaver County, UT

Beaver County, Utah Zone 6a June

This month in Beaver County, Utah

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 21
Avg. first frost September 29
Soil temp (4") 45°F
Watering High
Pest pressure High
Daylight 14.6 hrs
  1. Indoor seed-starting week for sunflower

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

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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.

Beaver County, Utah is in USDA Zone 6a. The average last spring frost is May 21 and the first fall frost is September 29, giving you a growing season of approximately 131 days.

At an elevation of 7,589 feet, Beaver County receives approximately 24.3 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
Beaver County, UT (Zone 6a) Short season
131 days
Last Spring Frost May 21
131 growing days
First Fall Frost September 29

Beaver County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 22 Transplant: May 20 🌸 Bloom: Aug 12 – Nov 4
Recommended (50%) ✗ May not fit
Start indoors: Apr 30 Transplant: May 28 🌸 Bloom: Aug 20 – Nov 12
Safe Start (90%) ✗ May not fit
Start indoors: May 20 Transplant: Jun 17 🌸 Bloom: Sep 9 – Dec 2

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 Beaver County

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

Soil pH

Your soil pH (6.5–7.8) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Sunflower.

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Sunflower.

How to Plant Sunflower

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

Succession Planting Sunflower

2
successive plantings in your 131-day season

Sow every 8 weeks. Last sowing by Jun 21 to harvest before frost.

Sunflower 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 1.7" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.3" 0" ❄️ Dormant
May 2.2" 2.9" 0" ✅ Rainfall sufficient
Jun 2.2" 1.6" 0.6" 💧 Light watering
Jul 2.2" 2.4" 0" ✅ Rainfall sufficient
Aug 2.2" 2.3" 0" ✅ Rainfall sufficient
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 2.3" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Beaver 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 1,801 GDD Excellent fit

Sunflower Planting Timeline — Beaver County, UT

Sunflower Planting Calendar

Activity When Date Range
Start Indoors April 30 Apr 30 – May 14
Transplant Outdoors May 28 May 28 – Jun 11
Direct Sow May 28 May 28 – Jun 18
Bloom August 20 Aug 20 – Nov 12

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August Bloom
September Bloom
October Bloom
November Bloom
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 6a

📆 Growing Season

131 days in Beaver County

Growing Tips for Sunflower in Beaver County

Direct sow Sunflower outdoors after May 21 in Beaver 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.

Beaver 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 Beaver County, UT?

Beaver County is in Zone 6a with an average last frost of May 21. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Beaver County, UT?

Beaver County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 21 and first fall frost is September 29.

🌱

Your Beaver County Garden Planner — Free

A 22-page printable planner built for Beaver County (Zone 6a). 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 Beaver County, UT. 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.