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When to Plant Savoy Cabbage in Cass County, IA

Savoy cabbage has crinkled, deeply veined leaves that form looser heads than regular cabbage. It has a milder, sweeter flavor and is more cold-tolerant.

Cass County, Iowa is in USDA Zone 5a. The average last spring frost is April 25 and the first fall frost is October 9, giving you a growing season of approximately 167 days.

At an elevation of 1,043 feet, Cass County receives approximately 31.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Savoy Cabbage during the growing season.

Cass County, IA (Zone 5a) Moderate season
167 days
Last Spring Frost April 25
167 growing days
First Fall Frost October 9

Cass County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (39 days to spare)
Start indoors: Mar 16 Transplant: Apr 20 🍅 Harvest: Jun 29 – Aug 24
Recommended (50%) ✓ Fits season (41 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: Jul 4 – Aug 29
Safe Start (90%) ✓ Fits season (39 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Jul 21 – Sep 15

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 Savoy Cabbage's growing requirements.

Soil pH

Your soil pH (6.2โ€“6.7) is within Savoy Cabbage's preferred range (6.0โ€“7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) โ€” Savoy Cabbage will thrive.

How to Plant Savoy Cabbage

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

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

Succession Planting Savoy Cabbage

2
successive plantings in your 167-day season

Sow every 8 weeks. Last sowing by Jun 21 to harvest before frost.

For a dedicated fall crop, sow by Jul 31.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 324 gal / 100 sq ft

Monthly Watering Guide for Savoy Cabbage

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

Month Savoy Cabbage Needs Rainfall You Supplement Action
Jan โ€” 1.5" 0" โ„๏ธ Dormant
Feb โ€” 1.6" 0" โ„๏ธ Dormant
Mar โ€” 1.9" 0" โ„๏ธ Dormant
Apr 4.3" 2.9" 1.4" ๐Ÿ’ง Light watering
May 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Jun 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Jul 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Aug 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Sep 4.3" 2.9" 1.4" ๐Ÿ’ง Light watering
Oct 4.3" 2.4" 1.9" ๐Ÿ’ง Light watering
Nov โ€” 2.1" 0" โ„๏ธ Dormant
Dec โ€” 1.9" 0" โ„๏ธ Dormant

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

Savoy Cabbage 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.

Savoy Cabbage needs ~1,305 GDD — county provides 2,421 GDD Excellent fit

Savoy Cabbage Planting Timeline โ€” Cass County, IA

Savoy Cabbage Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 โ€“ Apr 4
Transplant Outdoors April 25 Apr 25 โ€“ May 9
Direct Sow April 11 Apr 11 โ€“ May 2
Harvest July 4 Jul 4 โ€“ Aug 29
Fall Sowing July 31 Jul 31 โ€“ Aug 14

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

70โ€“110 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

167 days in Cass County

Growing Tips for Savoy Cabbage in Cass County

Direct sow Savoy Cabbage outdoors after April 25 in Cass County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors 4-6 weeks before last frost. Savoy cabbage is more forgiving of temperature fluctuations than smooth-leaved types. Excellent for stuffed cabbage rolls.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Savoy Cabbage in Cass County, IA?

Cass County is in Zone 5a with an average last frost of April 25. Plan your Savoy Cabbage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Cass County, IA?

Cass County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 25 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Cass County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Cass County, IA. Local conditions may vary. Last updated: April 2026.