Blog

When to plant Sunflower in Martin County County,

Martin County County sits in USDA Zone 10b. Plant Sunflower between December 7 (after last frost on January 25) and December 28.

When to Plant Sunflower in Martin County, FL

Martin County, Florida Zone 10b June

Your June game plan for Martin County, Florida

A quick June briefing for Martin County, Florida gardeners — what's urgent, what's next, and what can wait.

Avg. last frost January 25
Avg. first frost December 13
Soil temp (4") 90°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. Collect sunflower at their peak

    If you can't use it all right away, check the food-preservation section of your planner.

July prep starts now
  • First harvests: sunflower

Instant PDF download. No spam, unsubscribe any time.

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.

Martin County, Florida is in USDA Zone 10b. The average last spring frost is January 25 and the first fall frost is December 13, giving you a growing season of approximately 322 days.

At an elevation of 80 feet, Martin County receives approximately 56.3 inches of rainfall annually with predominantly sand soil. Summer highs average 88°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
Martin County, FL (Zone 10b) Year-round
322 days
Last Spring Frost January 25
322 growing days
First Fall Frost December 13
Share this guide:

Martin County Soil Profile

Soil Type

Sand

Soil pH

5.1-5.7

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✓ Fits season (97 days to spare)
Start indoors: Dec 25 Transplant: Nov 27 🌸 Bloom: Feb 19 – Sep 3
Recommended (50%) ✓ Fits season (91 days to spare)
Start indoors: Jan 4 Transplant: Dec 7 🌸 Bloom: Mar 1 – Sep 13
Safe Start (90%) ✓ Fits season (78 days to spare)
Start indoors: Jan 27 Transplant: Dec 30 🌸 Bloom: Mar 24 – Oct 6

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 Martin County

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

Soil pH

Your soil pH (5.1–5.7) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Martin 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 (1.5%). 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 322-day season

Sow every 8 weeks. Last sowing by Sep 04 to harvest before frost.

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
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 2.2" 2.8" 0" ✅ Rainfall sufficient
Feb 2.2" 3.1" 0" ✅ Rainfall sufficient
Mar 2.2" 3" 0" ✅ Rainfall sufficient
Apr 2.2" 2.3" 0" ✅ Rainfall sufficient
May 2.2" 3.4" 0" ✅ Rainfall sufficient
Jun 2.2" 8.6" 0" ✅ Rainfall sufficient
Jul 2.2" 7.9" 0" ✅ Rainfall sufficient
Aug 2.2" 8.4" 0" ✅ Rainfall sufficient
Sep 2.2" 8.2" 0" ✅ Rainfall sufficient
Oct 2.2" 4.2" 0" ✅ Rainfall sufficient
Nov 2.2" 2.2" 0" ✅ Rainfall sufficient
Dec 2.2" 2.1" 0.1" 💧 Light watering

Water needs are for active growing months only (Jan–Dec in Martin 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 ~1,360 GDD — county provides 5,168 GDD Excellent fit

Sunflower Planting Timeline — Martin County, FL

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 4 Jan 4 – Jan 18
Transplant Outdoors December 7 Dec 7 – Dec 21
Direct Sow December 7 Dec 7 – Dec 28
Bloom March 1 Mar 1 – Sep 13

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

Month-by-Month Timeline

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

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 10b

📆 Growing Season

322 days in Martin County

Growing Tips for Sunflower in Martin County

Direct sow Sunflower outdoors after January 25 in Martin County when soil has warmed and frost danger has passed.

Sandy soil in Martin 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 Martin County, FL?

Martin County is in Zone 10b with an average last frost of January 25. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Martin County, FL?

Martin County, Florida is in USDA Hardiness Zone 10b. The average last spring frost is January 25 and first fall frost is December 13.

When should I plant Sunflower in Martin County, ?

In Martin County, , plant Sunflower after the last frost (around January 25) and before the first frost (around December 13). Best results when soil holds above 50°F.

What growing zone is Martin County, for Sunflower?

Martin County sits in USDA Zone 10b. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.

Can Sunflower grow in Martin County's climate?

Yes — Sunflower grows well in Martin County's temperate climate. Martin County averages a 323-day frost-free season, with last frost around January 25 and first frost around December 13.

🌱

Your Martin County Garden Planner — Free

A 22-page printable planner built for Martin County (Zone 10b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Martin 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.