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When to Plant Napa Cabbage in Teton County, MT

Teton County, Montana Zone 4b May

May in Teton County, Montana — your action list

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 25
Avg. first frost September 16
Soil temp (4") 28°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Time to transplant napa cabbage

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Direct-sow napa cabbage

    Your soil is 28°F — warm enough for these to germinate without babying.

A few tasks this May that'll pay off in June
  • Fall sowing: napa cabbage

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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.

Teton County, Montana is in USDA Zone 4b. The average last spring frost is May 25 and the first fall frost is September 16, giving you a growing season of approximately 114 days.

At an elevation of 8,276 feet, Teton County receives approximately 15.1 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Napa Cabbage to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Napa Cabbage successfully. Mulch heavily to conserve soil moisture.

Teton County, MT (Zone 4b) Short season
114 days
Last Spring Frost May 25
114 growing days
First Fall Frost September 16

Teton County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (21 days to spare)
Start indoors: Apr 8 Transplant: May 20 🍅 Harvest: Jul 15 – Aug 19
Recommended (50%) ✓ Fits season (23 days to spare)
Start indoors: Apr 13 Transplant: May 25 🍅 Harvest: Jul 20 – Aug 24
Safe Start (90%) ✓ Fits season (18 days to spare)
Start indoors: Apr 30 Transplant: Jun 11 🍅 Harvest: Aug 6 – Sep 10

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 Teton County

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

Soil pH

Your soil pH (6.6–7.6) overlaps with Napa Cabbage's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Teton 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 moderate (2.2%). Annual compost additions will help Napa Cabbage.

How to Plant Napa Cabbage

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

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

Succession Planting Napa Cabbage

2
successive plantings in your 114-day season

Sow every 6.3 weeks. Last sowing by Jul 03 to harvest before frost.

For a dedicated fall crop, sow by Jun 24.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.7″/week
Watering frequency 2-3 times/week
Season total 1,697 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.1" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 6.5" 1.7" 4.8" 🚿 Regular watering
Jun 6.5" 1.2" 5.3" 🚿 Regular watering
Jul 6.5" 1.4" 5.1" 🚿 Regular watering
Aug 6.5" 1.7" 4.8" 🚿 Regular watering
Sep 6.5" 1.3" 5.2" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Teton 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 needs ~845 GDD — county provides 1,482 GDD Excellent fit

Napa Cabbage Planting Timeline — Teton County, MT

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors April 13 Apr 13 – Apr 27
Transplant Outdoors May 25 May 25 – Jun 8
Direct Sow May 18 May 18 – Jun 8
Harvest July 20 Jul 20 – Aug 24
Fall Sowing June 24 Jun 24 – Jul 8

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow Fall Sowing
July Fall Sowing Harvest
August 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: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

114 days in Teton County

Growing Tips for Napa Cabbage in Teton County

Direct sow Napa Cabbage outdoors after May 25 in Teton 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.

Teton County receives only 15" of rain annually. Napa Cabbage needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Napa Cabbage in Teton County, MT?

Teton County is in Zone 4b with an average last frost of May 25. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Teton County, MT?

Teton County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 25 and first fall frost is September 16.

🌱

Your Teton County Garden Planner — Free

A 24-page printable planner built for Teton County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Teton County, MT. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.