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When to Plant Sunflower in Kings County, CA

Kings County, California Zone 9a May

This month in Kings County, California

May is a pivotal month for Kings County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost February 14
Avg. first frost December 2
Soil temp (4") 72°F
Watering Critical
Pest pressure High
Daylight 13.9 hrs
  1. Harvest sunflower as they ripen

    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.

Kings County, California is in USDA Zone 9a. The average last spring frost is February 14 and the first fall frost is December 2, giving you a growing season of approximately 291 days.

At an elevation of 2,065 feet, Kings County receives approximately 18.8 inches of rainfall annually with predominantly loam soil. Summer highs average 102°F, so Sunflower may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Sunflower successfully. Mulch heavily to conserve soil moisture.

Kings County, CA (Zone 9a) Year-round
291 days
Last Spring Frost February 14
291 growing days
First Fall Frost December 2

Kings County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (171 days to spare)
Start indoors: Dec 20 Transplant: Feb 7 🍅 Harvest: Apr 18 – Jun 6
Recommended (50%) ✓ Fits season (165 days to spare)
Start indoors: Jan 3 Transplant: Feb 21 🍅 Harvest: May 2 – Jun 20
Safe Start (90%) ✓ Fits season (163 days to spare)
Start indoors: Jan 25 Transplant: Mar 15 🍅 Harvest: May 24 – Jul 12

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 Kings County

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

Soil pH

Your soil pH (6.5–7.4) is within Sunflower's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.1%). 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 291-day season

Sow every 8 weeks. Last sowing by Aug 24 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 716 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 3.6" 0" ❄️ Dormant
Feb 2.2" 4" 0" ✅ Rainfall sufficient
Mar 2.2" 3.2" 0" ✅ Rainfall sufficient
Apr 2.2" 1.4" 0.8" 💧 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" 0.7" 1.5" 🚿 Regular watering
Nov 2.2" 1.9" 0.3" 💧 Light watering
Dec 2.2" 3.2" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Kings 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 ~2,252 GDD — county provides 7,738 GDD Excellent fit

Sunflower Planting Timeline — Kings County, CA

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 3 Jan 3 – Jan 17
Transplant Outdoors February 21 Feb 21 – Mar 7
Direct Sow February 14 Feb 14 – Mar 7
Harvest May 2 May 2 – Jun 20

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

Month-by-Month Timeline

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

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 9a

📆 Growing Season

291 days in Kings County

Growing Tips for Sunflower in Kings County

Direct sow Sunflower outdoors after February 14 in Kings County when soil has warmed and frost danger has passed.

With summer highs reaching 102°F in Kings County, provide afternoon shade for Sunflower and water deeply in the morning.

Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Kings County receives only 19" 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 Kings County, CA?

Kings County is in Zone 9a with an average last frost of February 14. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kings County, CA?

Kings County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 14 and first fall frost is December 2.

🌱

Your Kings County Garden Planner — Free

A 24-page printable planner built for Kings County (Zone 9a). 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 Kings 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.