When to Plant Potatoes in St. Johns County, FL
Potatoes are a versatile staple crop that produces tubers underground. They come in hundreds of varieties with varying colors, textures, and maturity dates.
St. Johns County, Florida is in USDA Zone 9a. The average last spring frost is February 9 and the first fall frost is December 2, giving you a growing season of approximately 296 days.
At an elevation of 57 feet, St. Johns County receives approximately 51.1 inches of rainfall annually with predominantly sand soil. Summer highs average 99°F, so Potatoes may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Potatoes will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Potatoes root diseases.
St. Johns County Soil Profile
Soil Type
Sand
Soil pH
4.9-6.1
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 St. Johns County
How your county's soil matches Potatoes's growing requirements.
Soil pH
Your soil pH (4.9–6.1) overlaps with Potatoes's range (5.0–6.5), though not a perfect match.
Soil Texture
Sandy soil in St. Johns County warms quickly in spring but drains fast. Potatoes will need more frequent watering and regular compost additions to retain nutrients.
Organic Matter
Organic matter is low (1.5%). Add 2-3 inches of compost before planting Potatoes.
How to Plant Potatoes
Succession Planting Potatoes
Sow every 8 weeks. Last sowing by Aug 04 to harvest before frost.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Potatoes
Potatoes needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Potatoes Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.4" | 0" | ❄️ Dormant |
| Feb | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Mar | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Apr | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| May | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Jun | 4.3" | 7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 7.1" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 7.6" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 6.9" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Nov | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Dec | 4.3" | 2.3" | 2" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in St. Johns County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Potatoes 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.
Potatoes Planting Timeline — St. Johns County, FL
Potatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 29 | Dec 29 – Jan 12 |
| Transplant Outdoors | February 16 | Feb 16 – Mar 2 |
| Direct Sow | February 9 | Feb 9 – Mar 2 |
| Harvest | April 27 | Apr 27 – Jul 6 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Transplant Outdoors Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | Start Indoors |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
70–120 days
🧪 Soil pH
Needs 5–6.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 9a
📆 Growing Season
296 days in St. Johns County
Growing Tips for Potatoes in St. Johns County
Direct sow Potatoes outdoors after February 09 in St. Johns County when soil has warmed and frost danger has passed.
Sandy soil in St. Johns County dries quickly — mulch Potatoes 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 St. Johns County, provide afternoon shade for Potatoes and water deeply in the morning.
Common pests for Potatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
General growing tips
Plant seed potatoes (not grocery store potatoes) 4 inches deep in spring. Hill soil around stems as plants grow to prevent greening. Stop watering when plants die back.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Potatoes in Other Locations
Frequently Asked Questions
When should I plant Potatoes in St. Johns County, FL?
St. Johns County is in Zone 9a with an average last frost of February 9. Plan your Potatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Johns County, FL?
St. Johns County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is February 9 and first fall frost is December 2.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help St. Johns County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.