When to Plant Napa Cabbage in Alger County, MI
Napa cabbage forms tall, barrel-shaped heads with tender, crinkled leaves and a mild, slightly sweet flavor. It is the primary cabbage used for kimchi.
Alger County, Michigan is in USDA Zone 4b. The average last spring frost is May 10 and the first fall frost is October 16, giving you a growing season of approximately 159 days.
At an elevation of 1,014 feet, Alger County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Napa Cabbage to ensure they mature before fall.
Alger County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-7.1
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 Alger County
How your county's soil matches Napa Cabbage's growing requirements.
Soil pH
Your soil pH (6.3–7.1) is within Napa Cabbage's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Alger County is excellent for Napa Cabbage — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Napa Cabbage is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.
Organic Matter
Organic matter is excellent (4.8%) — Napa Cabbage will thrive.
How to Plant Napa Cabbage
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Napa Cabbage
Sow every 6.3 weeks. Last sowing by Aug 02 to harvest before frost.
For a dedicated fall crop, sow by Jul 24.
Plant Water Budget
Monthly Watering Guide for Napa Cabbage
Napa Cabbage needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.
| Month | Napa Cabbage Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2" | 0" | ❄️ Dormant |
| Feb | — | 2" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | — | 3.5" | 0" | ❄️ Dormant |
| May | 6.5" | 4.3" | 2.2" | 💧 Light watering |
| Jun | 6.5" | 5" | 1.5" | 💧 Light watering |
| Jul | 6.5" | 5" | 1.5" | 💧 Light watering |
| Aug | 6.5" | 4.7" | 1.8" | 💧 Light watering |
| Sep | 6.5" | 3.9" | 2.6" | 💧 Light watering |
| Oct | 6.5" | 3" | 3.5" | 🚿 Regular watering |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Alger County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Napa 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" — 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.
Napa Cabbage Planting Timeline — Alger County, MI
Napa Cabbage Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 29 | Mar 29 – Apr 12 |
| Transplant Outdoors | May 10 | May 10 – May 24 |
| Direct Sow | May 3 | May 3 – May 24 |
| Harvest | July 5 | Jul 5 – Aug 9 |
| Fall Sowing | July 24 | Jul 24 – Aug 7 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1.5"/week · 2-3 times/week
📅 Days to Maturity
55–75 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 4b
📆 Growing Season
159 days in Alger County
Growing Tips for Napa Cabbage in Alger County
Direct sow Napa Cabbage outdoors after May 10 in Alger County when soil has warmed and frost danger has passed.
Common pests for Napa Cabbage in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Best grown as a fall crop. Direct sow in late summer, 60-70 days before first frost. Keep soil evenly moist. Bolt-resistant varieties are available for spring planting.
Companion Planting
Good Companions
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Napa Cabbage in Other Locations
Frequently Asked Questions
When should I plant Napa Cabbage in Alger County, MI?
Alger County is in Zone 4b with an average last frost of May 10. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.
What planting zone is Alger County, MI?
Alger County, Michigan is in USDA Hardiness Zone 4b. The average last spring frost is May 10 and first fall frost is October 16.
Plan Your Garden with Confidence
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