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When to Plant Turnip in Tama County, IA

Tama County, Iowa Zone 5a May

Your May gardening checklist

Your Tama County, Iowa garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 28
Avg. first frost October 8
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs
  1. Harvest turnip as they ripen

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

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.

Tama County, Iowa is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 8, giving you a growing season of approximately 163 days.

At an elevation of 1,268 feet, Tama County receives approximately 38.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Turnip during the growing season.

Tama County, IA (Zone 5a) Moderate season
163 days
Last Spring Frost April 28
163 growing days
First Fall Frost October 8

Tama County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Transplant: Apr 22 🍅 Harvest: Jun 3 – Jul 8
Recommended (50%) ✓ Fits season (86 days to spare)
Transplant: Apr 28 🍅 Harvest: Jun 9 – Jul 14
Safe Start (90%) ✓ Fits season (80 days to spare)
Transplant: May 12 🍅 Harvest: Jun 23 – Jul 28

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 Tama County

How your county's soil matches Turnip's growing requirements.

Soil pH

Your soil pH (5.8–6.9) overlaps with Turnip's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Turnip.

Organic Matter

Organic matter is excellent (5.1%) — Turnip will thrive.

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

4
successive plantings in your 163-day season

Sow every 4.6 weeks. Last sowing by Aug 09 to harvest before frost.

For a dedicated fall crop, sow by Jul 30.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 527 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 1.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 2.6" 1.7" 💧 Light watering
Nov 3" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Tama 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 ~688 GDD — county provides 2,241 GDD Excellent fit

Turnip Planting Timeline — Tama County, IA

Turnip Planting Calendar

Activity When Date Range
Direct Sow April 14 Apr 14 – May 5
Harvest May 26 May 26 – Jun 30
Fall Sowing July 30 Jul 30 – Aug 13

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 5a

📆 Growing Season

163 days in Tama County

Growing Tips for Turnip in Tama County

Direct sow Turnip outdoors after April 28 in Tama County when soil has warmed and frost danger has passed.

Your generous 163.0-day season in Tama 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 Tama County, IA?

Tama County is in Zone 5a with an average last frost of April 28. Plan your Turnip planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tama County, IA?

Tama County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 8.

🌱

Your Tama County Garden Planner — Free

A 24-page printable planner built for Tama County (Zone 5a). 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 Tama County, IA. 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.