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When to plant Sunflower in Putnam County, FL

Plant Sunflower in Putnam County, when soil hits 50°F — usually January 12. Continue planting through February 2 for the spring crop.

When to Plant Sunflower in Putnam County, FL

Putnam County, Florida Zone 9b July

Top priorities for Putnam County, Florida gardeners in July

We've pulled the most time-sensitive tasks for Putnam County, Florida this July and put them front and centre. Tackle them in order.

Avg. last frost February 9
Avg. first frost December 2
Soil temp (4") 96°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. Start harvesting sunflower

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

A few tasks this July that'll pay off in August
  • 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.

Putnam County, Florida is in USDA Zone 9b. The average last spring frost is February 9 and the first fall frost is December 2, giving you a growing season of approximately 296 days.

At an elevation of 278 feet, Putnam County receives approximately 57.5 inches of rainfall annually with predominantly sand soil. Summer highs average 95°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
Putnam County, FL (Zone 9b) Year-round
296 days
Last Spring Frost February 9
296 growing days
First Fall Frost December 2

Putnam County Soil Profile

Soil Type

Sand

Soil pH

4.9-6.2

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✓ Fits season (80 days to spare)
Start indoors: Jan 4 Transplant: Dec 28 🌸 Bloom: Mar 22 – Sep 6
Recommended (50%) ✓ Fits season (72 days to spare)
Start indoors: Jan 19 Transplant: Jan 12 🌸 Bloom: Apr 6 – Sep 21
Safe Start (90%) ✓ Fits season (73 days to spare)
Start indoors: Feb 11 Transplant: Feb 4 🌸 Bloom: Apr 29 – Oct 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.

Soil Compatibility in Putnam County

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

Soil pH

Your soil pH (4.9–6.2) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Putnam 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 (1.4%). 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

5
successive plantings in your 296-day season

Sow every 8 weeks. Last sowing by Aug 24 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
Drought risk

Water stress score is 6/10 — 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 2.4" 0" ❄️ Dormant
Feb 2.2" 2.6" 0" ✅ Rainfall sufficient
Mar 2.2" 3.5" 0" ✅ Rainfall sufficient
Apr 2.2" 2.3" 0" ✅ Rainfall sufficient
May 2.2" 3.3" 0" ✅ Rainfall sufficient
Jun 2.2" 7.9" 0" ✅ Rainfall sufficient
Jul 2.2" 9.4" 0" ✅ Rainfall sufficient
Aug 2.2" 8.7" 0" ✅ Rainfall sufficient
Sep 2.2" 7.4" 0" ✅ Rainfall sufficient
Oct 2.2" 5.3" 0" ✅ Rainfall sufficient
Nov 2.2" 2.2" 0" ✅ Rainfall sufficient
Dec 2.2" 2.6" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Putnam 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 ~1,806 GDD — county provides 6,311 GDD Excellent fit

Sunflower Planting Timeline — Putnam County, FL

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 19 Jan 19 – Feb 2
Transplant Outdoors January 12 Jan 12 – Jan 26
Direct Sow January 12 Jan 12 – Feb 2
Bloom April 6 Apr 6 – Sep 21

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

Month-by-Month Timeline

MonthActivities
January Start Indoors Transplant Outdoors Direct Sow
February Start Indoors 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 9b

📆 Growing Season

296 days in Putnam County

Growing Tips for Sunflower in Putnam County

Direct sow Sunflower outdoors after February 09 in Putnam County when soil has warmed and frost danger has passed.

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

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 Putnam County, FL?

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

What planting zone is Putnam County, FL?

Putnam County, Florida is in USDA Hardiness Zone 9b. The average last spring frost is February 9 and first fall frost is December 2.

When should I plant Sunflower in Putnam County, FL?

In Putnam County, FL, plant Sunflower after the last frost (around February 9) and before the first frost (around December 2). Best results when soil holds above 50°F.

What growing zone is Putnam County, FL for Sunflower?

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

Can Sunflower grow in Putnam County's climate?

Yes — Sunflower grows well in Putnam County's temperate climate. Putnam County averages a 297-day frost-free season, with last frost around February 9 and first frost around December 2.

🌱

Your Putnam County Garden Planner — Free

A 22-page printable planner built for Putnam County (Zone 9b). 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 Putnam 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.