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When to Plant Turnip in Polk County, TN

Polk County, Tennessee Zone 7b May

May to-do list for Polk County, Tennessee

We've pulled the most time-sensitive tasks for Polk County, Tennessee this May and put them front and centre. Tackle them in order.

Avg. last frost April 19
Avg. first frost October 19
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
  1. Pick turnip

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

A few tasks this May that'll pay off in June
  • First harvests: turnip

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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.

Polk County, Tennessee is in USDA Zone 7b. The average last spring frost is April 19 and the first fall frost is October 19, giving you a growing season of approximately 183 days.

At an elevation of 1,255 feet, Polk County receives approximately 43.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Turnip during the growing season.

Polk County, TN (Zone 7b) Moderate season
183 days
Last Spring Frost April 19
183 growing days
First Fall Frost October 19
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Polk County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (112 days to spare)
Transplant: Apr 10 🍅 Harvest: May 22 – Jun 26
Recommended (50%) ✓ Fits season (106 days to spare)
Transplant: Apr 19 🍅 Harvest: May 31 – Jul 5
Safe Start (90%) ✓ Fits season (103 days to spare)
Transplant: May 5 🍅 Harvest: Jun 16 – Jul 21

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 Turnip's growing requirements.

Soil pH

Your soil pH (5.4–6.5) is more acidic than Turnip prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Polk County is excellent for Turnip — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Turnip.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Turnip.

How to Plant Turnip

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Turnip

5
successive plantings in your 183-day season

Sow every 4.6 weeks. Last sowing by Aug 20 to harvest before frost.

For a dedicated fall crop, sow by Aug 10.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 3.4" 0" ❄️ Dormant
Feb 3.8" 0" ❄️ Dormant
Mar 4.1" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 2.6" 1.7" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Polk 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 ~912 GDD — county provides 3,339 GDD Excellent fit

Turnip Planting Timeline — Polk County, TN

Turnip Planting Calendar

Activity When Date Range
Direct Sow April 5 Apr 5 – Apr 26
Harvest May 17 May 17 – Jun 21
Fall Sowing August 10 Aug 10 – Aug 24

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7b

📆 Growing Season

183 days in Polk County

Growing Tips for Turnip in Polk County

Direct sow Turnip outdoors after April 19 in Polk County when soil has warmed and frost danger has passed.

Your generous 183.0-day season in Polk 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 Polk County, TN?

Polk County is in Zone 7b with an average last frost of April 19. Plan your Turnip planting based on this frost date — see the calendar above for exact timing.

What planting zone is Polk County, TN?

Polk County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is April 19 and first fall frost is October 19.

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Your Polk County Garden Planner — Free

A 24-page printable planner built for Polk County (Zone 7b). 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 Polk County, TN. 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.