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When to Plant Napa Cabbage in Sanpete County, UT

Sanpete County, Utah Zone 6a May

Your May gardening checklist

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Sanpete County, Utah.

Avg. last frost May 21
Avg. first frost September 28
Soil temp (4") 38°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
  1. Transplant napa cabbage outside

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Direct-sow napa cabbage

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

Before June arrives, get these ready
  • Starting indoors: 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.

Sanpete County, Utah is in USDA Zone 6a. The average last spring frost is May 21 and the first fall frost is September 28, giving you a growing season of approximately 130 days.

At an elevation of 6,969 feet, Sanpete County receives approximately 14.2 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Napa Cabbage during the growing season. With low rainfall, drip irrigation is essential for growing Napa Cabbage successfully. Mulch heavily to conserve soil moisture.

Sanpete County, UT (Zone 6a) Short season
130 days
Last Spring Frost May 21
130 growing days
First Fall Frost September 28

Sanpete County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jul 8 – Aug 12
Recommended (50%) ✓ Fits season (39 days to spare)
Start indoors: Apr 16 Transplant: May 21 🍅 Harvest: Jul 16 – Aug 20
Safe Start (90%) ✓ Fits season (38 days to spare)
Start indoors: May 6 Transplant: Jun 10 🍅 Harvest: Aug 5 – Sep 9

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 Sanpete County

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

Soil pH

Your soil pH (6.5–7.8) overlaps with Napa Cabbage's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Sanpete 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 10 weeks before your first frost date for a fall harvest.

Succession Planting Napa Cabbage

2
successive plantings in your 130-day season

Sow every 6.3 weeks. Last sowing by Jul 15 to harvest before frost.

For a dedicated fall crop, sow by Jul 20.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.5″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 1,446 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" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 6.5" 1.7" 4.8" 🚿 Regular watering
Jun 6.5" 1" 5.5" 🚿 Regular watering
Jul 6.5" 1.4" 5.1" 🚿 Regular watering
Aug 6.5" 1.5" 5" 🚿 Regular watering
Sep 6.5" 1.3" 5.2" 🚿 Regular watering
Oct 1.1" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Sanpete 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 ~942 GDD — county provides 1,885 GDD Excellent fit

Napa Cabbage Planting Timeline — Sanpete County, UT

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors April 16 Apr 16 – Apr 30
Transplant Outdoors May 21 May 21 – Jun 4
Direct Sow May 7 May 7 – May 28
Harvest July 16 Jul 16 – Aug 20
Fall Sowing July 20 Jul 20 – Aug 3

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
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: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

130 days in Sanpete County

Growing Tips for Napa Cabbage in Sanpete County

Direct sow Napa Cabbage outdoors after May 21 in Sanpete 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.

Sanpete County receives only 14" 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 Sanpete County, UT?

Sanpete County is in Zone 6a with an average last frost of May 21. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sanpete County, UT?

Sanpete County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 21 and first fall frost is September 28.

🌱

Your Sanpete County Garden Planner — Free

A 24-page printable planner built for Sanpete County (Zone 6a). 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 Sanpete County, UT. 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.