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When to Plant Napa Cabbage in Clay County, SD

Clay County, South Dakota Zone 5a April

Clay County, South Dakota gardeners: here's your April plan

Your garden in Clay County, South Dakota is working on a schedule, even when you're not. Here's where you should be this April.

Avg. last frost April 30
Avg. first frost October 7
Soil temp (4") 47°F
Watering Moderate
Pest pressure Low
Daylight 13.2 hrs
  1. Move napa cabbage into the garden

    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

    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.

Clay County, South Dakota is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 7, giving you a growing season of approximately 160 days.

At an elevation of 663 feet, Clay County receives approximately 30.8 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Napa Cabbage to ensure they mature before fall.

Clay County, SD (Zone 5a) Moderate season
160 days
Last Spring Frost April 30
160 growing days
First Fall Frost October 7

Clay County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (72 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jun 18 – Jul 23
Recommended (50%) ✓ Fits season (69 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jun 25 – Jul 30
Safe Start (90%) ✓ Fits season (66 days to spare)
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: Jul 10 – Aug 14

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 Clay 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 Clay County is excellent for Napa Cabbage — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) — Napa Cabbage will thrive.

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

3
successive plantings in your 160-day season

Sow every 6.3 weeks. Last sowing by Jul 24 to harvest before frost.

For a dedicated fall crop, sow by Jul 29.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,182 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 0.8" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 6.5" 3.6" 2.9" 💧 Light watering
May 6.5" 4.8" 1.7" 💧 Light watering
Jun 6.5" 4.6" 1.9" 💧 Light watering
Jul 6.5" 3.4" 3.1" 💧 Light watering
Aug 6.5" 3.8" 2.7" 💧 Light watering
Sep 6.5" 3" 3.5" 🚿 Regular watering
Oct 6.5" 1.7" 4.8" 🚿 Regular watering
Nov 1.2" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Clay 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 ~796 GDD — county provides 1,960 GDD Excellent fit

Napa Cabbage Planting Timeline — Clay County, SD

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 – Apr 9
Transplant Outdoors April 30 Apr 30 – May 14
Direct Sow April 16 Apr 16 – May 7
Harvest June 25 Jun 25 – Jul 30
Fall Sowing July 29 Jul 29 – Aug 12

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Fall Sowing Harvest
August Fall Sowing
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 5a

📆 Growing Season

160 days in Clay County

Growing Tips for Napa Cabbage in Clay County

Direct sow Napa Cabbage outdoors after April 30 in Clay 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 Clay County, SD?

Clay County is in Zone 5a with an average last frost of April 30. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clay County, SD?

Clay County, South Dakota is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 7.

🌱

Your Clay County Garden Planner — Free

A 24-page printable planner built for Clay County (Zone 5a). 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 Clay County, SD. Local conditions may vary. Last updated: April 2026.

Sources & credits

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