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When to Plant Sunflower in Del Norte County, CA

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.

Del Norte County, California is in USDA Zone 8b. The average last spring frost is March 27 and the first fall frost is November 20, giving you a growing season of approximately 238 days.

At an elevation of 72 feet, Del Norte County receives approximately 43.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 89ยฐF, providing good warmth for Sunflower during the growing season. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Sunflower will need more frequent watering and organic matter to retain nutrients.

Del Norte County, CA (Zone 8b) Long season
238 days
Last Spring Frost March 27
238 growing days
First Fall Frost November 20

Del Norte County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.9-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (104 days to spare)
Start indoors: Jan 15 Transplant: Mar 19 🍅 Harvest: May 28 – Jul 16
Recommended (50%) ✓ Fits season (105 days to spare)
Start indoors: Feb 6 Transplant: Apr 10 🍅 Harvest: Jun 19 – Aug 7
Safe Start (90%) ✓ Fits season (94 days to spare)
Start indoors: Mar 16 Transplant: May 18 🍅 Harvest: Jul 27 – Sep 14

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.

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
Sunflower needs ~1,424 GDD — county provides 3,986 GDD Excellent fit

Sunflower Planting Timeline โ€” Del Norte County, CA

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 6 Feb 6 โ€“ Feb 20
Transplant Outdoors April 10 Apr 10 โ€“ Apr 24
Direct Sow April 3 Apr 3 โ€“ Apr 24
Harvest June 19 Jun 19 โ€“ Aug 7

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 8b

Growing Season

238 days

Growing Tips for Del Norte County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Sunflower in Del Norte County, CA?

Del Norte County is in Zone 8b with an average last frost of March 27. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Del Norte County, CA?

Del Norte County, California is in USDA Hardiness Zone 8b. The average last spring frost is March 27 and first fall frost is November 20.

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Plan Your Garden with Confidence

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

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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 Del Norte County, CA. Local conditions may vary. Last updated: April 2026.