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When to Plant Turnip in St. Johns County, FL

St. Johns County, Florida Zone 9b May

Your May game plan for St. Johns County, Florida

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Avg. last frost February 9
Avg. first frost December 2
Soil temp (4") 77°F
Watering Moderate
Pest pressure High
Daylight 13.5 hrs

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Turnips are a fast-growing cool-season root vegetable with edible roots and greens. Baby turnips are sweet and tender while mature ones are more pungent.

St. Johns County, Florida is in USDA Zone 9b. 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 Turnip may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Turnip will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Turnip root diseases.

St. Johns County, FL (Zone 9b) Year-round
296 days
Last Spring Frost February 9
296 growing days
First Fall Frost December 2

St. Johns County Soil Profile

Soil Type

Sand

Soil pH

4.9-6.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (230 days to spare)
Transplant: Jan 25 🍅 Harvest: Mar 8 – Apr 12
Recommended (50%) ✓ Fits season (219 days to spare)
Transplant: Feb 9 🍅 Harvest: Mar 23 – Apr 27
Safe Start (90%) ✓ Fits season (210 days to spare)
Transplant: Mar 11 🍅 Harvest: Apr 22 – May 27

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 Turnip's growing requirements.

Soil pH

Your soil pH (4.9–6.1) is more acidic than Turnip prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in St. Johns County warms quickly in spring but drains fast. Turnip 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 Turnip.

How to Plant Turnip

0.5"
Planting Depth
4"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Turnip

9
successive plantings in your 296-day season

Sow every 4.6 weeks. Last sowing by Oct 03 to harvest before frost.

For a dedicated fall crop, sow by Oct 07.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 880 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Turnip

Turnip needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Turnip 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.

Turnip 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.

Turnip needs ~1,212 GDD — county provides 7,202 GDD Excellent fit

Turnip Planting Timeline — St. Johns County, FL

Turnip Planting Calendar

Activity When Date Range
Direct Sow January 19 Jan 19 – Feb 9
Harvest March 2 Mar 2 – Apr 6
Fall Sowing October 7 Oct 7 – Oct 21

Plant 0.5" deep · 4" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January Direct Sow
February Direct Sow
March Harvest
April Harvest
May
June
July
August
September
October Fall Sowing
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

296 days in St. Johns County

Growing Tips for Turnip in St. Johns County

Direct sow Turnip 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 Turnip 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 Turnip and water deeply in the morning.

Your generous 297.0-day season in St. Johns County allows multiple plantings of Turnip. Sow every 20.0 days for continuous harvest.

Common pests for Turnip in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in early spring or late summer. Harvest when roots are 2-3 inches in diameter for best flavor. Both the roots and the greens are nutritious and edible.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Turnip in St. Johns County, FL?

St. Johns County is in Zone 9b with an average last frost of February 9. Plan your Turnip 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 9b. The average last spring frost is February 9 and first fall frost is December 2.

🌱

Your St. Johns County Garden Planner — Free

A 24-page printable planner built for St. Johns County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for St. Johns County, FL. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.