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When to Plant Napa Cabbage in Sanborn County, SD

Sanborn County, South Dakota Zone 4b April

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

A quick April briefing for Sanborn County, South Dakota gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 2
Avg. first frost October 5
Soil temp (4") 42°F
Watering High
Pest pressure Low
Daylight 13.2 hrs
  1. Plant napa cabbage from seed, right in the garden

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

A few tasks this April that'll pay off in May
  • Transplants going out: 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.

Sanborn County, South Dakota is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 5, giving you a growing season of approximately 156 days.

At an elevation of 860 feet, Sanborn County receives approximately 22.3 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Napa Cabbage to ensure they mature before fall.

Sanborn County, SD (Zone 4b) Moderate season
156 days
Last Spring Frost May 2
156 growing days
First Fall Frost October 5

Sanborn County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (67 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🍅 Harvest: Jun 22 – Jul 27
Recommended (50%) ✓ Fits season (65 days to spare)
Start indoors: Mar 21 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 1
Safe Start (90%) ✓ Fits season (62 days to spare)
Start indoors: Apr 3 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 Sanborn County

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

Soil pH

Your soil pH (6.7–7.2) is within Napa Cabbage's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Napa Cabbage will thrive.

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.

Succession Planting Napa Cabbage

3
successive plantings in your 156-day season

Sow every 6.3 weeks. Last sowing by Jul 22 to harvest before frost.

For a dedicated fall crop, sow by Jul 13.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,499 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 0.6" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 6.5" 3.1" 3.4" 🚿 Regular watering
Jun 6.5" 3.8" 2.7" 💧 Light watering
Jul 6.5" 3" 3.5" 🚿 Regular watering
Aug 6.5" 2.8" 3.7" 🚿 Regular watering
Sep 6.5" 2" 4.5" 🚿 Regular watering
Oct 6.5" 1.5" 5" 🚿 Regular watering
Nov 0.7" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Sanborn 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 ~650 GDD — county provides 1,560 GDD Excellent fit

Napa Cabbage Planting Timeline — Sanborn County, SD

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 25 Apr 25 – May 16
Harvest June 27 Jun 27 – Aug 1
Fall Sowing July 13 Jul 13 – Jul 27

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 4b

📆 Growing Season

156 days in Sanborn County

Growing Tips for Napa Cabbage in Sanborn County

Direct sow Napa Cabbage outdoors after May 02 in Sanborn 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.

Sanborn County receives only 22" 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 Sanborn County, SD?

Sanborn County is in Zone 4b with an average last frost of May 2. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sanborn County, SD?

Sanborn County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 5.

🌱

Your Sanborn County Garden Planner — Free

A 24-page printable planner built for Sanborn 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.

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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 Sanborn 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.