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When to Plant Savoy Cabbage in Boundary County, ID

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.

Boundary County, Idaho is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is September 22, giving you a growing season of approximately 135 days.

At an elevation of 5,105 feet, Boundary County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Savoy Cabbage during the growing season.

Boundary County, ID (Zone 5b) Short season
135 days
Last Spring Frost May 10
135 growing days
First Fall Frost September 22

Boundary County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (11 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jul 10 – Sep 4
Recommended (50%) ✓ Fits season (9 days to spare)
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Jul 19 – Sep 13
Safe Start (90%) ✓ Fits season (6 days to spare)
Start indoors: Apr 30 Transplant: Jun 4 🍅 Harvest: Aug 13 – Oct 8

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 Boundary County

How your county's soil matches Savoy Cabbage's growing requirements.

Soil pH

Your soil pH (6.7โ€“8.3) overlaps with Savoy Cabbage's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Savoy Cabbage.

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 135-day season

Sow every 8 weeks. Last sowing by Jun 04 to harvest before frost.

For a dedicated fall crop, sow by Jul 14.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 495 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

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€” 1.6" 0" โ„๏ธ Dormant
Feb โ€” 1.2" 0" โ„๏ธ Dormant
Mar โ€” 1.9" 0" โ„๏ธ Dormant
Apr โ€” 2" 0" โ„๏ธ Dormant
May 4.3" 2.7" 1.6" ๐Ÿ’ง Light watering
Jun 4.3" 1.6" 2.7" ๐Ÿšฟ Regular watering
Jul 4.3" 1.8" 2.5" ๐Ÿšฟ Regular watering
Aug 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Sep 4.3" 1.6" 2.7" ๐Ÿšฟ Regular watering
Oct โ€” 2.1" 0" โ„๏ธ Dormant
Nov โ€” 1.5" 0" โ„๏ธ Dormant
Dec โ€” 1.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Boundary 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 ~1,372 GDD — county provides 2,058 GDD Excellent fit

Savoy Cabbage Planting Timeline โ€” Boundary County, ID

Savoy Cabbage Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 โ€“ Apr 19
Transplant Outdoors May 10 May 10 โ€“ May 24
Direct Sow April 26 Apr 26 โ€“ May 17
Harvest July 19 Jul 19 โ€“ Sep 13
Fall Sowing July 14 Jul 14 โ€“ Jul 28

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors Direct Sow
May Transplant Outdoors 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

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

70โ€“110 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

135 days in Boundary County

Growing Tips for Savoy Cabbage in Boundary County

Direct sow Savoy Cabbage outdoors after May 10 in Boundary 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.

Boundary County receives only 21" of rain annually. Savoy Cabbage needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

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 Boundary County, ID?

Boundary County is in Zone 5b with an average last frost of May 10. Plan your Savoy Cabbage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Boundary County, ID?

Boundary County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is May 10 and first fall frost is September 22.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Boundary County gardeners in Zone 5b 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 Boundary County, ID. Local conditions may vary. Last updated: April 2026.