When to plant Onion in Polk County County,
Spring Onion in Polk County County goes in January 4–January 25, once nighttime temps stop dipping near freezing. A second sowing from October 24 to November 7 extends the harvest into fall.
When to Plant Onion in Polk County, FL
What to do in June
A quick June briefing for Polk County, Florida gardeners — what's urgent, what's next, and what can wait.
-
It's harvest week for onion
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.
Polk County, Florida is in USDA Zone 10a. The average last spring frost is January 25 and the first fall frost is December 19, giving you a growing season of approximately 328 days.
At an elevation of 236 feet, Polk County receives approximately 58.3 inches of rainfall annually with predominantly sand soil. Summer highs average 96°F, so Onion may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Onion will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.
Polk County Soil Profile
Soil Type
Sand
Soil pH
4.9-6.3
Drainage
Well Drained
Onion 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 Polk County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (4.9–6.3) is more acidic than Onion prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
Sandy soil in Polk County warms quickly in spring but drains fast. Onion will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Onion.
Organic Matter
Organic matter is low (1.6%). Add 2-3 inches of compost before planting Onion.
How to Plant Onion
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Onion Water Budget
Monthly Watering Guide for Onion
Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Onion Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Feb | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Mar | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Apr | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| May | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jun | 4.3" | 9" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 9.1" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 7.9" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 6.7" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Nov | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Dec | 4.3" | 2.4" | 1.9" | 💧 Light watering |
Water needs are for active growing months only (Jan–Dec in Polk County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion 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.
Onion Planting Timeline — Polk County, FL
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 28 | Dec 28 – Jan 11 |
| Transplant Outdoors | January 25 | Jan 25 – Feb 8 |
| Direct Sow | January 4 | Jan 4 – Jan 25 |
| Harvest | April 26 | Apr 26 – Jun 14 |
| Fall Sowing | October 24 | Oct 24 – Nov 7 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Transplant Outdoors Direct Sow |
| February | Transplant Outdoors |
| March | — |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| November | Fall Sowing |
| December | Start Indoors |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 10a
📆 Growing Season
328 days in Polk County
Growing Tips for Onion in Polk County
Direct sow Onion outdoors after January 25 in Polk County when soil has warmed and frost danger has passed.
Sandy soil in Polk County dries quickly — mulch Onion 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 Polk County, provide afternoon shade for Onion and water deeply in the morning.
Common pests for Onion in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in Polk County, FL?
Polk County is in Zone 10a with an average last frost of January 25. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Polk County, FL?
Polk County, Florida is in USDA Hardiness Zone 10a. The average last spring frost is January 25 and first fall frost is December 19.
When should I plant Onion in Polk County, ?
In Polk County, , plant Onion after the last frost (around January 25) and before the first frost (around December 19). Best results when soil holds above 50°F.
What growing zone is Polk County, for Onion?
Polk County sits in USDA Zone 10a. Onion grows reliably in zones 3a through 10b, so it's a good fit here.
Can Onion grow in Polk County's climate?
Yes — Onion grows well in Polk County's temperate climate. Polk County averages a 329-day frost-free season, with last frost around January 25 and first frost around December 19.
Your Polk County Garden Planner — Free
A 22-page printable planner built for Polk County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.