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When to Plant Sunflower in Santa Barbara County, CA

Santa Barbara County, California Zone 10a May

May to-do list for Santa Barbara County, California

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

Avg. last frost February 28
Avg. first frost November 24
Soil temp (4") 73°F
Watering Critical
Pest pressure High
Daylight 13.8 hrs
  1. Basket week: sunflower

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

A few tasks this May that'll pay off in June
  • First harvests: sunflower

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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.

Santa Barbara County, California is in USDA Zone 10a. The average last spring frost is February 28 and the first fall frost is November 24, giving you a growing season of approximately 269 days.

At an elevation of 2,364 feet, Santa Barbara County receives approximately 19.9 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Sunflower during the growing season. With low rainfall, drip irrigation is essential for growing Sunflower successfully. Mulch heavily to conserve soil moisture.

Santa Barbara County, CA (Zone 10a) Long season
269 days
Last Spring Frost February 28
269 growing days
First Fall Frost November 24
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Santa Barbara County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (147 days to spare)
Start indoors: Jan 1 Transplant: Feb 19 🍅 Harvest: Apr 30 – Jun 18
Recommended (50%) ✓ Fits season (143 days to spare)
Start indoors: Jan 17 Transplant: Mar 7 🍅 Harvest: May 16 – Jul 4
Safe Start (90%) ✓ Fits season (131 days to spare)
Start indoors: Feb 24 Transplant: Apr 14 🍅 Harvest: Jun 23 – Aug 11

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 Santa Barbara County

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

Soil pH

Your soil pH (6.5–7.2) is within Sunflower's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

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

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
30"
Between Rows

Succession Planting Sunflower

4
successive plantings in your 269-day season

Sow every 8 weeks. Last sowing by Aug 16 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 549 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 4" 0" ❄️ Dormant
Feb 2.2" 4.6" 0" ✅ Rainfall sufficient
Mar 2.2" 2.9" 0" ✅ Rainfall sufficient
Apr 2.2" 1.8" 0.4" 💧 Light watering
May 2.2" 0.5" 1.7" 🚿 Regular watering
Jun 2.2" 0.1" 2.1" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.2" 2" 🚿 Regular watering
Oct 2.2" 0.8" 1.4" 🚿 Regular watering
Nov 2.2" 2.1" 0.1" 💧 Light watering
Dec 2.9" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Santa Barbara 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 ~1,424 GDD — county provides 4,522 GDD Excellent fit

Sunflower Planting Timeline — Santa Barbara County, CA

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 17 Jan 17 – Jan 31
Transplant Outdoors March 7 Mar 7 – Mar 21
Direct Sow February 28 Feb 28 – Mar 21
Harvest May 16 May 16 – Jul 4

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 10a

📆 Growing Season

269 days in Santa Barbara County

Growing Tips for Sunflower in Santa Barbara County

Direct sow Sunflower outdoors after February 28 in Santa Barbara 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.

Santa Barbara County receives only 20" of rain annually. Sunflower needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Santa Barbara County, CA?

Santa Barbara County is in Zone 10a with an average last frost of February 28. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Santa Barbara County, CA?

Santa Barbara County, California is in USDA Hardiness Zone 10a. The average last spring frost is February 28 and first fall frost is November 24.

🌱

Your Santa Barbara County Garden Planner — Free

A 24-page printable planner built for Santa Barbara County (Zone 10a). 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 Santa Barbara County, CA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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