When to plant Sunflower in Union County, FL
For Union County, gardeners: plant Sunflower February 8 through March 1 once soil reads 50°F.
When to Plant Sunflower in Union County, FL
Top priorities for Union County, Florida gardeners in June
Each item below is timed to Union County, Florida's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Collect sunflower at their peak
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Before July arrives, get these ready
- First harvests: sunflower
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.
Union County, Florida is in USDA Zone 9a. The average last spring frost is March 1 and the first fall frost is November 27, giving you a growing season of approximately 271 days.
At an elevation of 360 feet, Union County receives approximately 60.6 inches of rainfall annually with predominantly sand soil. Summer highs average 96°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.
Union County Soil Profile
Soil Type
Sand
Soil pH
5.2-6
Drainage
Well Drained
Sunflower Planting Risk Windows
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 Union County
How your county's soil matches Sunflower's growing requirements.
Soil pH
Your soil pH (5.2–6.0) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
Sandy soil in Union 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
Succession Planting Sunflower
Sow every 8 weeks. Last sowing by Aug 19 to harvest before frost.
Sunflower Water Budget
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 | — | 3.1" | 0" | ❄️ Dormant |
| Feb | — | 2.7" | 0" | ❄️ Dormant |
| Mar | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 2.8" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 8.1" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 10" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 9" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 7.2" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| Dec | — | 2.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Union 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 Planting Timeline — Union County, FL
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 8 | Feb 8 – Feb 22 |
| Transplant Outdoors | February 8 | Feb 8 – Feb 22 |
| Direct Sow | February 8 | Feb 8 – Mar 1 |
| Bloom | May 3 | May 3 – Oct 4 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | Direct Sow |
| April | — |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| 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
271 days in Union County
Growing Tips for Sunflower in Union County
Direct sow Sunflower outdoors after March 01 in Union County when soil has warmed and frost danger has passed.
Sandy soil in Union 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 96°F in Union 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
Check more plant combinations with our Companion Planting Checker →
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Union County, FL?
Union County is in Zone 9a with an average last frost of March 1. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, FL?
Union County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is March 1 and first fall frost is November 27.
When should I plant Sunflower in Union County, FL?
In Union County, FL, plant Sunflower after the last frost (around March 1) and before the first frost (around November 27). Best results when soil holds above 50°F.
What growing zone is Union County, FL for Sunflower?
Union 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 Union County's climate?
Yes — Sunflower grows well in Union County's temperate climate. Union County averages a 271-day frost-free season, with last frost around March 1 and first frost around November 27.
Your Union County Garden Planner — Free
A 22-page printable planner built for Union 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.