Blog

When to Plant Napa Cabbage in Sublette County, WY

Sublette County, Wyoming Zone 4b May

What to do in May

May is a pivotal month for Sublette County, Wyoming gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost June 22
Avg. first frost August 24
Soil temp (4") 36°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
A few tasks this May that'll pay off in June
  • Transplants going out: napa cabbage
  • Direct-sowing: napa cabbage
  • Fall sowing: napa cabbage

Instant PDF download. No spam, unsubscribe any time.

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.

Sublette County, Wyoming is in USDA Zone 4b. The average last spring frost is June 22 and the first fall frost is August 24, giving you a growing season of approximately 63 days.

At an elevation of 5,005 feet, Sublette County receives approximately 22.8 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Napa Cabbage to ensure they mature before fall.

Sublette County, WY (Zone 4b) Very short season
63 days
Last Spring Frost June 22
63 growing days
First Fall Frost August 24

Sublette County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 6 Transplant: Jun 17 🍅 Harvest: Aug 12 – Sep 16
Recommended (50%) ✗ May not fit
Start indoors: May 11 Transplant: Jun 22 🍅 Harvest: Aug 17 – Sep 21
Safe Start (90%) ✗ May not fit
Start indoors: May 19 Transplant: Jun 30 🍅 Harvest: Aug 25 – Sep 29

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 Sublette County

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

Soil pH

Your soil pH (6.7–7.8) overlaps with Napa Cabbage's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Sublette County is excellent for Napa Cabbage — good drainage, moisture retention, and nutrient holding capacity.

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.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.5″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.8" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 2.5" 0" ❄️ Dormant
Jun 6.5" 1.5" 5" 🚿 Regular watering
Jul 6.5" 2.2" 4.3" 🚿 Regular watering
Aug 6.5" 2.1" 4.4" 🚿 Regular watering
Sep 1.7" 0" ❄️ Dormant
Oct 2" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Aug in Sublette 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 ~699 GDD — county provides 677 GDD Tight fit

Napa Cabbage Planting Timeline — Sublette County, WY

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors May 11 May 11 – May 25
Transplant Outdoors June 22 Jun 22 – Jul 6
Direct Sow June 15 Jun 15 – Jul 6
Harvest August 17 Aug 17 – Sep 21
Fall Sowing June 1 Jun 1 – Jun 15

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · Natural rainfall sufficient

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

63 days in Sublette County

Growing Tips for Napa Cabbage in Sublette County

Direct sow Napa Cabbage outdoors after June 22 in Sublette County when soil has warmed and frost danger has passed.

Your 63.0-day growing season in Sublette County is tight for Napa Cabbage (55.0-75.0 days to maturity). Start indoors and choose early-maturing varieties.

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.

Sublette County receives only 23" 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 Sublette County, WY?

Sublette County is in Zone 4b with an average last frost of June 22. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sublette County, WY?

Sublette County, Wyoming is in USDA Hardiness Zone 4b. The average last spring frost is June 22 and first fall frost is August 24.

🌱

Your Sublette County Garden Planner — Free

A 24-page printable planner built for Sublette 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Sublette County, WY. 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.