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When to Plant Rutabaga in Cass County, MN

Rutabagas are a cross between turnips and cabbage, producing large yellow-fleshed roots with a sweet, mild flavor. They are excellent mashed, roasted, or in stews.

Cass County, Minnesota is in USDA Zone 3b. The average last spring frost is May 12 and the first fall frost is September 28, giving you a growing season of approximately 139 days.

At an elevation of 938 feet, Cass County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Rutabaga to ensure they mature before fall.

Cass County, MN (Zone 3b) Short season
139 days
Last Spring Frost May 12
139 growing days
First Fall Frost September 28

Cass County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (19 days to spare)
Transplant: May 8 🍅 Harvest: Jul 31 – Sep 4
Recommended (50%) ✓ Fits season (20 days to spare)
Transplant: May 12 🍅 Harvest: Aug 4 – Sep 8
Safe Start (90%) ✓ Fits season (18 days to spare)
Transplant: May 27 🍅 Harvest: Aug 19 – Sep 23

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 Cass County

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

Soil pH

Your soil pH (5.9โ€“6.9) overlaps with Rutabaga's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The silt loam soil in Cass County is excellent for Rutabaga โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.6%) โ€” Rutabaga will thrive.

How to Plant Rutabaga

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Rutabaga

Rutabaga needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Rutabaga Needs Rainfall You Supplement Action
Jan โ€” 1.3" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 2.1" 0" โ„๏ธ Dormant
Apr โ€” 3" 0" โ„๏ธ Dormant
May 3" 3.5" 0" โœ… Rainfall sufficient
Jun 3" 3.9" 0" โœ… Rainfall sufficient
Jul 3" 3.8" 0" โœ… Rainfall sufficient
Aug 3" 3.5" 0" โœ… Rainfall sufficient
Sep 3" 3.2" 0" โœ… Rainfall sufficient
Oct โ€” 2.5" 0" โ„๏ธ Dormant
Nov โ€” 2.2" 0" โ„๏ธ Dormant
Dec โ€” 2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Cass County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Rutabaga 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" โ€” every day above 50ยฐF 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.

Rutabaga needs ~900 GDD — county provides 1,390 GDD Excellent fit

Rutabaga Planting Timeline โ€” Cass County, MN

Rutabaga Planting Calendar

Activity When Date Range
Direct Sow May 5 May 5 โ€“ May 26
Harvest July 28 Jul 28 โ€“ Sep 1
Fall Sowing July 6 Jul 6 โ€“ Jul 20

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.7"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

80โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 3b

๐Ÿ“† Growing Season

139 days in Cass County

Growing Tips for Rutabaga in Cass County

Direct sow Rutabaga outdoors after May 12 in Cass County when soil has warmed and frost danger has passed.

Common pests for Rutabaga 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 summer for fall harvest. Thin seedlings to 6-8 inches apart. Flavor improves significantly after a few light frosts.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rutabaga in Cass County, MN?

Cass County is in Zone 3b with an average last frost of May 12. Plan your Rutabaga planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Cass County, MN?

Cass County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 12 and first fall frost is September 28.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Cass County gardeners in Zone 3b 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.

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