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When to plant Sunflower in Miami-Dade County, FL

Miami-Dade County sits in USDA Zone 11a. Plant Sunflower between November 6 (after last frost on January 1) and November 27.

When to Plant Sunflower in Miami-Dade County, FL

Miami-Dade County, Florida Zone 11a June

What to do in June

Each item below is timed to Miami-Dade County, Florida's frost dates and soil temperatures. Skip nothing, stress about nothing.

Soil temp (4") 89°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Survive, don't thrive

    June-August is endurance gardening. Keep okra, peppers, sweet potatoes, and southern peas alive. Harvest everything daily before the heat damages produce on the vine.

  2. Start fall tomato seeds indoors

    Yes, indoors — under lights or in AC. They'll be ready to transplant in August when temperatures briefly moderate.

  3. Add compost to empty beds

    Empty beds get a thick layer of compost + mulch to suppress weeds and feed the soil for fall planting.

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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.

Miami-Dade County, Florida is in USDA Zone 11a. The average last spring frost is January 1 and the first fall frost is December 31, giving you a growing season of approximately 364 days.

At an elevation of 123 feet, Miami-Dade County receives approximately 58.7 inches of rainfall annually with predominantly sand soil. Summer highs average 90°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
Miami-Dade County, FL (Zone 11a) Year-round
365 days
Last Spring Frost No frost
365 growing days
First Fall Frost No frost

Miami-Dade County Soil Profile

Soil Type

Sand

Soil pH

5.1-6.3

Drainage

Well Drained

Soil Compatibility in Miami-Dade County

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

Soil pH

Your soil pH (5.1–6.3) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Miami-Dade 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
0.7″/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 2.2" 2.9" 0" ✅ Rainfall sufficient
Feb 2.2" 2.9" 0" ✅ Rainfall sufficient
Mar 2.2" 3.4" 0" ✅ Rainfall sufficient
Apr 2.2" 2.5" 0" ✅ Rainfall sufficient
May 2.2" 3.8" 0" ✅ Rainfall sufficient
Jun 2.2" 8.1" 0" ✅ Rainfall sufficient
Jul 2.2" 9.5" 0" ✅ Rainfall sufficient
Aug 2.2" 8.6" 0" ✅ Rainfall sufficient
Sep 2.2" 7.1" 0" ✅ Rainfall sufficient
Oct 2.2" 5" 0" ✅ Rainfall sufficient
Nov 2.2" 2.3" 0" ✅ Rainfall sufficient
Dec 2.2" 2.7" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Jan–Dec in Miami-Dade 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 ~1,488 GDD — county provides 6,387 GDD Excellent fit

Sunflower Planting Timeline — Miami-Dade County, FL

Sunflower Planting Calendar

Activity When Date Range
Start Indoors December 11 Dec 11 – Dec 25
Transplant Outdoors November 6 Nov 6 – Nov 20
Direct Sow November 6 Nov 6 – Nov 27
Bloom January 29 Jan 29 – Aug 27

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

Month-by-Month Timeline

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

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 11a

📆 Growing Season

365 days in Miami-Dade County

Growing Tips for Sunflower in Miami-Dade County

Sandy soil in Miami-Dade 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 Miami-Dade County, FL?

Miami-Dade County is in Zone 11a with an average last frost of January 1. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Miami-Dade County, FL?

Miami-Dade County, Florida is in USDA Hardiness Zone 11a. The average last spring frost is January 1 and first fall frost is December 31.

When should I plant Sunflower in Miami-Dade County, FL?

In Miami-Dade 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 Miami-Dade County, FL for Sunflower?

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

Can Sunflower grow in Miami-Dade County's climate?

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

🌱

Your Miami-Dade County Garden Planner — Free

A 22-page printable planner built for Miami-Dade County (Zone 11a). 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 Miami-Dade County, FL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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