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When to Plant Sunflower in Lane County, OR

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.

Lane County, Oregon is in USDA Zone 8a. 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 81ยฐF, 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.

Lane County, OR (Zone 8a) 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

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Start indoors: Feb 23 Transplant: Apr 27 🍅 Harvest: Jul 6 – Aug 24
Recommended (50%) ✓ Fits season (54 days to spare)
Start indoors: Mar 3 Transplant: May 5 🍅 Harvest: Jul 14 – Sep 1
Safe Start (90%) ✓ Fits season (59 days to spare)
Start indoors: Mar 23 Transplant: May 25 🍅 Harvest: Aug 3 – Sep 21

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 (5.7โ€“6.4) overlaps with Sunflower's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The silt loam soil in Lane County is excellent for Sunflower โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) โ€” Sunflower will thrive.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
30"
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.

Plant 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 โ€” 7.6" 0" โ„๏ธ Dormant
Feb โ€” 5.3" 0" โ„๏ธ Dormant
Mar โ€” 5.3" 0" โ„๏ธ Dormant
Apr 2.2" 4" 0" โœ… Rainfall sufficient
May 2.2" 2.5" 0" โœ… Rainfall sufficient
Jun 2.2" 1.6" 0.6" ๐Ÿ’ง Light watering
Jul 2.2" 0.8" 1.4" ๐Ÿšฟ Regular watering
Aug 2.2" 0.9" 1.3" ๐Ÿšฟ Regular watering
Sep 2.2" 2" 0.2" ๐Ÿ’ง Light watering
Oct 2.2" 4.3" 0" โœ… Rainfall sufficient
Nov โ€” 8.3" 0" โ„๏ธ Dormant
Dec โ€” 8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Lane County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 โ€” Lane County, OR

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 3 Mar 3 โ€“ Mar 17
Transplant Outdoors May 5 May 5 โ€“ May 19
Direct Sow April 28 Apr 28 โ€“ May 19
Harvest July 14 Jul 14 โ€“ Sep 1

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Direct Sow
May Transplant Outdoors Direct Sow
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

70โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† 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 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 Lane County, OR?

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

What planting zone is Lane County, OR?

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

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Lane County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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: April 2026.