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When to plant Sunflower in Monroe County, FL

The best window to plant Sunflower in Monroe County, is November 20–December 11, when soil warms to 50°F. Last frost typically hits January 1; first frost December 31.

When to Plant Sunflower in Monroe County, FL

Monroe County, Florida Zone 11b July

July to-do list for Monroe County, Florida

Your Monroe County, Florida garden is entering a new phase. Here's what's on the schedule for July and why each task matters now.

Avg. last frost January 22
Soil temp (4") 94°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. Harvest sunflower as they ripen

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

To set up a strong August, finish these tasks
  • 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.

Monroe County, Florida is in USDA Zone 11b. The average last spring frost is January 22 and the first fall frost is April 15, giving you a growing season of approximately 83 days.

At an elevation of 169 feet, Monroe County receives approximately 55.6 inches of rainfall annually with predominantly sand soil. Summer highs average 93°F, providing good warmth for Sunflower during the growing season. 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
Monroe County, FL (Zone 11b) Year-round
365 days
Last Spring Frost No frost
365 growing days
First Fall Frost No frost

Monroe County Soil Profile

Soil Type

Sand

Soil pH

4.8-5.7

Drainage

Well Drained

Soil Compatibility in Monroe County

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

Soil pH

Your soil pH (4.8–5.7) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Monroe 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 (1.3%). Add 2-3 inches of compost before planting Sunflower.

How to Plant Sunflower

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

Sunflower Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 33 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 2.2" 2.3" 0" ✅ Rainfall sufficient
Feb 2.2" 2.7" 0" ✅ Rainfall sufficient
Mar 2.2" 3.8" 0" ✅ Rainfall sufficient
Apr 2.2" 2.5" 0" ✅ Rainfall sufficient
May 2.2" 3.2" 0" ✅ Rainfall sufficient
Jun 2.2" 7.1" 0" ✅ Rainfall sufficient
Jul 2.2" 8.2" 0" ✅ Rainfall sufficient
Aug 2.2" 8.7" 0" ✅ Rainfall sufficient
Sep 2.2" 7.7" 0" ✅ Rainfall sufficient
Oct 2.2" 4.8" 0" ✅ Rainfall sufficient
Nov 2.2" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (Jan–Oct in Monroe 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 ~1,679 GDD — county provides 7,208 GDD Excellent fit

Sunflower Planting Timeline — Monroe County, FL

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 1 Jan 1 – Jan 15
Transplant Outdoors November 20 Nov 20 – Dec 4
Direct Sow November 20 Nov 20 – Dec 11
Bloom February 12 Feb 12 – Sep 24

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

Month-by-Month Timeline

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

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: too_acidic

🗺️ USDA Zone

Zone 11b

📆 Growing Season

365 days in Monroe County

Growing Tips for Sunflower in Monroe County

Direct sow Sunflower outdoors after January 22 in Monroe County when soil has warmed and frost danger has passed.

Sandy soil in Monroe 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 Monroe County, FL?

Monroe County is in Zone 11b with an average last frost of January 22. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monroe County, FL?

Monroe County, Florida is in USDA Hardiness Zone 11b. The average last spring frost is January 22 and first fall frost is .

When should I plant Sunflower in Monroe County, FL?

In Monroe County, FL, plant Sunflower after the last frost (around January 1) and before the first frost (around December 31). Best results when soil holds above 50°F.

What growing zone is Monroe County, FL for Sunflower?

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

Can Sunflower grow in Monroe County's climate?

Yes — Sunflower grows well in Monroe County's temperate climate. Monroe County averages a 365-day frost-free season, with last frost around January 1 and first frost around December 31.

🌱

Your Monroe County Garden Planner — Free

A 22-page printable planner built for Monroe County (Zone 11b). 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 Monroe 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.