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When to Plant Napa Cabbage in Humboldt County, NV

Humboldt County, Nevada Zone 6b May

Your May planting checklist for Humboldt County, Nevada

Each item below is timed to Humboldt County, Nevada's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 30
Avg. first frost September 15
Soil temp (4") 44°F
Watering Critical
Pest pressure Low
Daylight 14.3 hrs
  1. Move napa cabbage from tray to bed

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

  2. Scatter napa cabbage into prepared beds

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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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.

Humboldt County, Nevada is in USDA Zone 6b. The average last spring frost is May 30 and the first fall frost is September 15, giving you a growing season of approximately 108 days.

At an elevation of 5,527 feet, Humboldt County receives approximately 8.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94°F, providing good warmth for Napa Cabbage during the growing season. Sandy soil warms quickly in spring — great for early planting — but Napa Cabbage will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Napa Cabbage successfully. Mulch heavily to conserve soil moisture.

Humboldt County, NV (Zone 6b) Short season
108 days
Last Spring Frost May 30
108 growing days
First Fall Frost September 15

Humboldt County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (19 days to spare)
Start indoors: Apr 17 Transplant: May 22 🍅 Harvest: Jul 17 – Aug 21
Recommended (50%) ✓ Fits season (17 days to spare)
Start indoors: Apr 25 Transplant: May 30 🍅 Harvest: Jul 25 – Aug 29
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: May 14 Transplant: Jun 18 🍅 Harvest: Aug 13 – Sep 17

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 Humboldt County

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

Soil pH

Your soil pH (7.2–8.6) is more alkaline than Napa Cabbage prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Humboldt County warms quickly in spring but drains fast. Napa Cabbage will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Napa Cabbage is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is low (0.9%). Add 2-3 inches of compost before planting 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 108-day season

Sow every 6.3 weeks. Last sowing by Jul 02 to harvest before frost.

For a dedicated fall crop, sow by Jul 07.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.3″/week
You supply
2.0″/week
Watering frequency 2-3 times/week
Season total 1,881 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 0.6" 0" ❄️ Dormant
Feb 0.5" 0" ❄️ Dormant
Mar 0.4" 0" ❄️ Dormant
Apr 0.3" 0" ❄️ Dormant
May 6.5" 0.2" 6.3" 🚿 Regular watering
Jun 6.5" 0.3" 6.2" 🚿 Regular watering
Jul 6.5" 1.3" 5.2" 🚿 Regular watering
Aug 6.5" 1.6" 4.9" 🚿 Regular watering
Sep 6.5" 1.1" 5.4" 🚿 Regular watering
Oct 0.8" 0" ❄️ Dormant
Nov 0.4" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Humboldt 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 ~1,332 GDD — county provides 2,214 GDD Excellent fit

Napa Cabbage Planting Timeline — Humboldt County, NV

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors April 25 Apr 25 – May 9
Transplant Outdoors May 30 May 30 – Jun 13
Direct Sow May 16 May 16 – Jun 6
Harvest July 25 Jul 25 – Aug 29
Fall Sowing July 7 Jul 7 – Jul 21

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
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: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

108 days in Humboldt County

Growing Tips for Napa Cabbage in Humboldt County

Direct sow Napa Cabbage outdoors after May 30 in Humboldt County when soil has warmed and frost danger has passed.

Sandy soil in Humboldt County dries quickly — mulch Napa Cabbage with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

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.

Humboldt County receives only 8" 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 Humboldt County, NV?

Humboldt County is in Zone 6b with an average last frost of May 30. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Humboldt County, NV?

Humboldt County, Nevada is in USDA Hardiness Zone 6b. The average last spring frost is May 30 and first fall frost is September 15.

🌱

Your Humboldt County Garden Planner — Free

A 24-page printable planner built for Humboldt County (Zone 6b). 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 Humboldt County, NV. 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.