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When to Plant Kale in Roberts County, SD

Roberts County, South Dakota Zone 4b May

This month in Roberts County, South Dakota

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

Avg. last frost May 2
Avg. first frost October 6
Soil temp (4") 55°F
Watering Moderate
Pest pressure Low
Daylight 14.7 hrs
  1. Move kale into the garden

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

Looking ahead to June
  • Starting indoors: kale
  • First harvests: kale

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Kale is an exceptionally hardy, nutrient-dense green available in curly, lacinato, and Russian varieties. It tolerates heavy frost and often tastes sweeter after cold exposure.

Roberts County, South Dakota is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 6, giving you a growing season of approximately 157 days.

At an elevation of 961 feet, Roberts County receives approximately 23.3 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Kale to ensure they mature before fall.

Roberts County, SD (Zone 4b) Moderate season
157 days
Last Spring Frost May 2
157 growing days
First Fall Frost October 6

Roberts 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 (48 days to spare)
Start indoors: Mar 14 Transplant: Apr 25 🍅 Harvest: Jun 20 – Aug 15
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Mar 21 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 22
Safe Start (90%) ✓ Fits season (42 days to spare)
Start indoors: Apr 4 Transplant: May 16 🍅 Harvest: Jul 11 – Sep 5

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 Roberts County

How your county's soil matches Kale's growing requirements.

Soil pH

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

Soil Texture

The loam soil in Roberts County is excellent for Kale — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Kale.

How to Plant Kale

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 Kale

3
successive plantings in your 157-day season

Sow every 5.7 weeks. Last sowing by Jul 28 to harvest before frost.

For a dedicated fall crop, sow by Jul 14.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.6″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 247 gal / 100 sq ft

Monthly Watering Guide for Kale

Kale needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Kale Needs Rainfall You Supplement Action
Jan 0.6" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 3.5" 3.5" 0" ✅ Rainfall sufficient
Jun 3.5" 4.1" 0" ✅ Rainfall sufficient
Jul 3.5" 3.2" 0.3" 💧 Light watering
Aug 3.5" 2.4" 1.1" 💧 Light watering
Sep 3.5" 1.9" 1.6" 💧 Light watering
Oct 3.5" 1.4" 2.1" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

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

Kale 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.

Kale needs ~600 GDD — county provides 1,570 GDD Excellent fit

Kale Planting Timeline — Roberts County, SD

Kale 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 22
Fall Sowing July 14 Jul 14 – Jul 28

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

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Only during dry spells

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

157 days in Roberts County

Growing Tips for Kale in Roberts County

Direct sow Kale outdoors after May 02 in Roberts County when soil has warmed and frost danger has passed.

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

General growing tips

Direct sow or transplant in early spring or late summer. Harvest outer leaves first to keep plants productive. Kale overwinters in many climates and can provide greens all year.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Kale Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow 2nd year flower stalks to dry. Harvest pods when tan.
Storage Store airtight; viable 5 years at 35°F, under 50% humidity.

Isolate 1/2 mile from other brassicas (broccoli, cabbage, etc.) — they all cross.

Frequently Asked Questions

When should I plant Kale in Roberts County, SD?

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

What planting zone is Roberts County, SD?

Roberts County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 6.

🌱

Your Roberts County Garden Planner — Free

A 24-page printable planner built for Roberts 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.

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 Roberts 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.