When to Plant Sunflower in Alachua County, FL
Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.
Alachua County, Florida is in USDA Zone 9a. The average last spring frost is February 23 and the first fall frost is November 27, giving you a growing season of approximately 277 days.
At an elevation of 398 feet, Alachua County receives approximately 50 inches of rainfall annually with predominantly sand soil. Summer highs average 99°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.
Alachua County Soil Profile
Soil Type
Sand
Soil pH
5.2-6.1
Drainage
Well Drained
Plant 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 Alachua County
How your county's soil matches Sunflower's growing requirements.
Soil pH
Your soil pH (5.2–6.1) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
Sandy soil in Alachua 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 (1.6%). 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.
Plant Water Budget
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 | — | 2.6" | 0" | ❄️ Dormant |
| Feb | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| Mar | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 2.5" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 7.5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 7.4" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 6.3" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 6.8" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 4.6" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Alachua 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 — Alachua County, FL
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 12 | Jan 12 – Jan 26 |
| Transplant Outdoors | March 2 | Mar 2 – Mar 16 |
| Direct Sow | February 23 | Feb 23 – Mar 16 |
| Harvest | May 11 | May 11 – Jun 29 |
Plant 1" deep · 18" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | — |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| 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 9a
📆 Growing Season
277 days in Alachua County
Growing Tips for Sunflower in Alachua County
Direct sow Sunflower outdoors after February 23 in Alachua County when soil has warmed and frost danger has passed.
Sandy soil in Alachua 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 99°F in Alachua 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 after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.
Companion Planting
Good Companions
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Check more plant combinations with our Companion Planting Checker →
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Alachua County, FL?
Alachua County is in Zone 9a with an average last frost of February 23. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Alachua County, FL?
Alachua County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is February 23 and first fall frost is November 27.
Plan Your Garden with Confidence
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