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When to Plant Sunflower in Lane County, OR

Lane County, Oregon Zone 8b June

This month in Lane County, Oregon

Your Lane County, Oregon garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 21
Avg. first frost October 25
Soil temp (4") 79°F
Watering High
Pest pressure High
Daylight 15.3 hrs
  1. Basket week: sunflower

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

July prep starts now
  • 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.

Lane County, Oregon is in USDA Zone 8b. The average last spring frost is April 21 and the first fall frost is October 25, giving you a growing season of approximately 187 days.

At an elevation of 48 feet, Lane County receives approximately 50.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Sunflower to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Lane County, OR (Zone 8b) Moderate season
187 days
Last Spring Frost April 21
187 growing days
First Fall Frost October 25

Lane County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.4

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 23 Transplant: Mar 30 🌸 Bloom: Jun 22 – Nov 9
Recommended (50%) ✗ May not fit
Start indoors: Mar 31 Transplant: Apr 7 🌸 Bloom: Jun 30 – Nov 17
Safe Start (90%) ✗ May not fit
Start indoors: Apr 20 Transplant: Apr 27 🌸 Bloom: Jul 20 – Dec 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 Lane County

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

Soil pH

Your soil pH (5.7–6.4) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Lane 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 187-day season

Sow every 8 weeks. Last sowing by Jul 17 to harvest before frost.

Sunflower Water Budget

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

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 7.6" 0" ❄️ Dormant
Feb 5.3" 0" ❄️ Dormant
Mar 5.3" 0" ❄️ Dormant
Apr 2.2" 4" 0" ✅ Rainfall sufficient
May 2.2" 2.5" 0" ✅ Rainfall sufficient
Jun 2.2" 1.6" 0.6" 💧 Light watering
Jul 2.2" 0.8" 1.4" 🚿 Regular watering
Aug 2.2" 0.9" 1.3" 🚿 Regular watering
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 2.2" 4.3" 0" ✅ Rainfall sufficient
Nov 8.3" 0" ❄️ Dormant
Dec 8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Lane 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 2,010 GDD Excellent fit

Sunflower Planting Timeline — Lane County, OR

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 31 Mar 31 – Apr 14
Transplant Outdoors April 7 Apr 7 – Apr 21
Direct Sow April 7 Apr 7 – Apr 28
Bloom June 30 Jun 30 – Nov 17

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
June Bloom
July Bloom
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 8b

📆 Growing Season

187 days in Lane County

Growing Tips for Sunflower in Lane County

Direct sow Sunflower outdoors after April 21 in Lane 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 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 Lane County, OR?

Lane County is in Zone 8b with an average last frost of April 21. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lane County, OR?

Lane County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 21 and first fall frost is October 25.

🌱

Your Lane County Garden Planner — Free

A 22-page printable planner built for Lane County (Zone 8b). 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 Lane County, OR. 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.