When to Plant Turnip in Iron County, WI
May in Iron County, Wisconsin — your action list
Welcome to May in Zone 4a. These are the moves that will have the biggest impact on your growing season.
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Plant turnip from seed, right in the garden
Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.
Before June arrives, get these ready
- First harvests: turnip
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.
Iron County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 22 and the first fall frost is September 25, giving you a growing season of approximately 126 days.
At an elevation of 841 feet, Iron County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Turnip to ensure they mature before fall.
Iron County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.9
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 Iron County
How your county's soil matches Turnip's growing requirements.
Soil pH
Your soil pH (5.7–6.9) overlaps with Turnip's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Iron County is excellent for Turnip — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.6%) — Turnip will thrive.
How to Plant Turnip
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Turnip
Sow every 4.6 weeks. Last sowing by Jul 27 to harvest before frost.
For a dedicated fall crop, sow by Jul 03.
Plant Water Budget
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 | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.4" | 0" | ❄️ Dormant |
| Apr | — | 3" | 0" | ❄️ Dormant |
| May | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Jun | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Jul | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Aug | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Sep | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Oct | — | 2.5" | 0" | ❄️ Dormant |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Iron 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 Planting Timeline — Iron County, WI
Turnip Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 15 | May 15 – Jun 5 |
| Harvest | June 26 | Jun 26 – Jul 31 |
| Fall Sowing | July 3 | Jul 3 – Jul 17 |
Plant 0.5" deep · 4" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Direct Sow |
| June | Direct Sow Harvest |
| July | Fall Sowing Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
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: acceptable
🗺️ USDA Zone
Zone 4a
📆 Growing Season
126 days in Iron County
Growing Tips for Turnip in Iron County
Direct sow Turnip outdoors after May 22 in Iron County when soil has warmed and frost danger has passed.
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
Check more plant combinations with our Companion Planting Checker →
Turnip in Other Locations
Frequently Asked Questions
When should I plant Turnip in Iron County, WI?
Iron County is in Zone 4a with an average last frost of May 22. Plan your Turnip planting based on this frost date — see the calendar above for exact timing.
What planting zone is Iron County, WI?
Iron County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 22 and first fall frost is September 25.
Your Iron County Garden Planner — Free
A 24-page printable planner built for Iron County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.