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When to Plant Kai Lan in Haakon County, SD

Haakon County, South Dakota Zone 4b May

Top priorities for Haakon County, South Dakota gardeners in May

Welcome to May in Zone 4b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 14
Avg. first frost September 28
Soil temp (4") 54°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
  1. Transplant kai lan outside

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Put kai lan seeds straight in the ground

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

Coming up in June — start thinking about
  • Starting indoors: kai lan

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Kai lan (Chinese broccoli) is a brassica grown for its thick, glossy stems and small flower buds. It has a slightly bitter, broccoli-like flavor essential in Cantonese cooking.

Haakon County, South Dakota is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is September 28, giving you a growing season of approximately 137 days.

At an elevation of 1,097 feet, Haakon County receives approximately 22.5 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Kai Lan to ensure they mature before fall.

Haakon County, SD (Zone 4b) Short season
137 days
Last Spring Frost May 14
137 growing days
First Fall Frost September 28

Haakon County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Start indoors: Mar 28 Transplant: May 9 🍅 Harvest: Jun 27 – Jul 25
Recommended (50%) ✓ Fits season (60 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Jul 2 – Jul 30
Safe Start (90%) ✓ Fits season (57 days to spare)
Start indoors: Apr 14 Transplant: May 26 🍅 Harvest: Jul 14 – Aug 11

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 Haakon County

How your county's soil matches Kai Lan's growing requirements.

Soil pH

Your soil pH (6.5–7.5) is within Kai Lan's preferred range (6.0–7.5).

Soil Texture

The loam soil in Haakon County is excellent for Kai Lan — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Kai Lan.

Organic Matter

Organic matter is excellent (4.1%) — Kai Lan will thrive.

How to Plant Kai Lan

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Kai Lan

3
successive plantings in your 137-day season

Sow every 5.1 weeks. Last sowing by Jul 30 to harvest before frost.

For a dedicated fall crop, sow by Jul 06.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 893 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Kai Lan

Kai Lan needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Kai Lan Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 4.3" 2.6" 1.7" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 1.9" 2.4" 🚿 Regular watering
Aug 4.3" 2.3" 2" 💧 Light watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.8" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Haakon County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Kai Lan 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.

Kai Lan needs ~564 GDD — county provides 1,472 GDD Excellent fit

Kai Lan Planting Timeline — Haakon County, SD

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 7 May 7 – May 28
Harvest July 2 Jul 2 – Jul 30
Fall Sowing July 6 Jul 6 – Jul 20

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

137 days in Haakon County

Growing Tips for Kai Lan in Haakon County

Direct sow Kai Lan outdoors after May 14 in Haakon County when soil has warmed and frost danger has passed.

Common pests for Kai Lan in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

Haakon County receives only 22" of rain annually. Kai Lan needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow in spring or fall. Harvest when flower buds first appear but before they open. Cut stems at the base to encourage side shoots. Prefers cool weather.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Kai Lan in Haakon County, SD?

Haakon County is in Zone 4b with an average last frost of May 14. Plan your Kai Lan planting based on this frost date — see the calendar above for exact timing.

What planting zone is Haakon County, SD?

Haakon County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is September 28.

🌱

Your Haakon County Garden Planner — Free

A 24-page printable planner built for Haakon 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 Haakon County, SD. 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.