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When to plant Sunflower in Clay County, FL

Plant Sunflower in Clay County from January 28 to February 18 in spring. Clay County sits in USDA Zone 9a, with last frost around February 18 and first frost on November 27.

When to Plant Sunflower in Clay County, FL

Clay County, Florida Zone 9a July

July in the garden — Clay County, Florida

Here's what deserves your attention in Clay County, Florida this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost February 18
Avg. first frost November 27
Soil temp (4") 93°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Start harvesting sunflower

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

August will be here before you know it — start on
  • 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.

Clay County, Florida is in USDA Zone 9a. The average last spring frost is February 18 and the first fall frost is November 27, giving you a growing season of approximately 282 days.

At an elevation of 122 feet, Clay County receives approximately 54.3 inches of rainfall annually with predominantly sand soil. Summer highs average 99°F, so Sunflower may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Sunflower will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Clay County, FL (Zone 9a) Year-round
282 days
Last Spring Frost February 18
282 growing days
First Fall Frost November 27

Clay County Soil Profile

Soil Type

Sand

Soil pH

5-5.8

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✓ Fits season (64 days to spare)
Start indoors: Jan 19 Transplant: Jan 19 🌸 Bloom: Apr 13 – Sep 14
Recommended (50%) ✓ Fits season (65 days to spare)
Start indoors: Jan 28 Transplant: Jan 28 🌸 Bloom: Apr 22 – Sep 23
Safe Start (90%) ✓ Fits season (56 days to spare)
Start indoors: Mar 1 Transplant: Mar 1 🌸 Bloom: May 24 – Oct 25

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 Clay County

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

Soil pH

Your soil pH (5.0–5.8) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Clay County warms quickly in spring but drains fast. Sunflower will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Sunflower.

Organic Matter

Organic matter is low (1.6%). Add 2-3 inches of compost before planting Sunflower.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Sunflower

4
successive plantings in your 282-day season

Sow every 8 weeks. Last sowing by Aug 19 to harvest before frost.

Sunflower Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/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 2.6" 0" ❄️ Dormant
Feb 2.2" 3" 0" ✅ Rainfall sufficient
Mar 2.2" 3.1" 0" ✅ Rainfall sufficient
Apr 2.2" 2.5" 0" ✅ Rainfall sufficient
May 2.2" 4" 0" ✅ Rainfall sufficient
Jun 2.2" 8.5" 0" ✅ Rainfall sufficient
Jul 2.2" 7.4" 0" ✅ Rainfall sufficient
Aug 2.2" 7.4" 0" ✅ Rainfall sufficient
Sep 2.2" 6.6" 0" ✅ Rainfall sufficient
Oct 2.2" 5.1" 0" ✅ Rainfall sufficient
Nov 2.2" 2.1" 0.1" 💧 Light watering
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Clay 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 ~2,061 GDD — county provides 6,862 GDD Excellent fit

Sunflower Planting Timeline — Clay County, FL

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 28 Jan 28 – Feb 11
Transplant Outdoors January 28 Jan 28 – Feb 11
Direct Sow January 28 Jan 28 – Feb 18
Bloom April 22 Apr 22 – Sep 23

Plant 1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors Transplant Outdoors Direct Sow
February Start Indoors Transplant Outdoors Direct Sow
March
April Bloom
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October
November
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: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

282 days in Clay County

Growing Tips for Sunflower in Clay County

Direct sow Sunflower outdoors after February 18 in Clay County when soil has warmed and frost danger has passed.

Sandy soil in Clay County dries quickly — mulch Sunflower with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 99°F in Clay 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.

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 Clay County, FL?

Clay County is in Zone 9a with an average last frost of February 18. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clay County, FL?

Clay County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is February 18 and first fall frost is November 27.

When should I plant Sunflower in Clay County, FL?

In Clay County, FL, plant Sunflower after the last frost (around February 18) and before the first frost (around November 27). Best results when soil holds above 50°F.

What growing zone is Clay County, FL for Sunflower?

Clay County sits in USDA Zone 9a. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.

Can Sunflower grow in Clay County's climate?

Yes — Sunflower grows well in Clay County's temperate climate. Clay County averages a 283-day frost-free season, with last frost around February 18 and first frost around November 27.

🌱

Your Clay County Garden Planner — Free

A 22-page printable planner built for Clay 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 Clay County, FL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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