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When to Plant Napa Cabbage in Somerset County, NJ

Somerset County, New Jersey Zone 7a May

This month in Somerset County, New Jersey

Your Somerset County, New Jersey garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost March 29
Avg. first frost November 12
Soil temp (4") 62°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Start napa cabbage indoors

    Label every cell. You will absolutely forget which is which otherwise.

  2. Start harvesting napa cabbage

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

To set up a strong June, finish these tasks
  • First harvests: 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.

Somerset County, New Jersey is in USDA Zone 7a. The average last spring frost is March 29 and the first fall frost is November 12, giving you a growing season of approximately 228 days.

At an elevation of 182 feet, Somerset County receives approximately 45.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Napa Cabbage during the growing season.

Somerset County, NJ (Zone 7a) Long season
228 days
Last Spring Frost March 29
228 growing days
First Fall Frost November 12

Somerset County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (137 days to spare)
Start indoors: Feb 18 Transplant: Mar 25 🍅 Harvest: May 20 – Jun 24
Recommended (50%) ✓ Fits season (137 days to spare)
Start indoors: Feb 22 Transplant: Mar 29 🍅 Harvest: May 24 – Jun 28
Safe Start (90%) ✓ Fits season (146 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: Jun 4 – Jul 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 Somerset County

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

Soil pH

Your soil pH (4.9–6.7) is more acidic than Napa Cabbage prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). 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

4
successive plantings in your 228-day season

Sow every 6.3 weeks. Last sowing by Aug 29 to harvest before frost.

For a dedicated fall crop, sow by Sep 03.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,339 gal / 100 sq ft

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 3.1" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 6.5" 4.2" 2.3" 💧 Light watering
Apr 6.5" 4" 2.5" 💧 Light watering
May 6.5" 3.9" 2.6" 💧 Light watering
Jun 6.5" 4.4" 2.1" 💧 Light watering
Jul 6.5" 4.4" 2.1" 💧 Light watering
Aug 6.5" 4.4" 2.1" 💧 Light watering
Sep 6.5" 3.5" 3" 💧 Light watering
Oct 6.5" 4.2" 2.3" 💧 Light watering
Nov 6.5" 3.3" 3.2" 💧 Light watering
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Somerset 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 ~1,138 GDD — county provides 3,990 GDD Excellent fit

Napa Cabbage Planting Timeline — Somerset County, NJ

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors February 22 Feb 22 – Mar 8
Transplant Outdoors March 29 Mar 29 – Apr 12
Direct Sow March 15 Mar 15 – Apr 5
Harvest May 24 May 24 – Jun 28
Fall Sowing September 3 Sep 3 – Sep 17

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7a

📆 Growing Season

228 days in Somerset County

Growing Tips for Napa Cabbage in Somerset County

Direct sow Napa Cabbage outdoors after March 29 in Somerset 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

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Napa Cabbage in Somerset County, NJ?

Somerset County is in Zone 7a with an average last frost of March 29. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Somerset County, NJ?

Somerset County, New Jersey is in USDA Hardiness Zone 7a. The average last spring frost is March 29 and first fall frost is November 12.

🌱

Your Somerset County Garden Planner — Free

A 24-page printable planner built for Somerset County (Zone 7a). 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 Somerset County, NJ. 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.