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When to Plant Kohlrabi in Golden Valley County, MT

Golden Valley County, Montana Zone 4b May

Top priorities for Golden Valley County, Montana gardeners in May

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Golden Valley County, Montana.

Avg. last frost May 22
Avg. first frost September 20
Soil temp (4") 30°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
  1. Move kohlrabi into the garden

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Scatter kohlrabi into prepared beds

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

June will be here before you know it — start on
  • Fall sowing: kohlrabi

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Kohlrabi is an unusual brassica that forms a swollen stem above ground with a mild, sweet turnip-like flavor. Both the bulb and tender leaves are edible.

Golden Valley County, Montana is in USDA Zone 4b. The average last spring frost is May 22 and the first fall frost is September 20, giving you a growing season of approximately 121 days.

At an elevation of 7,917 feet, Golden Valley County receives approximately 25 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Kohlrabi to ensure they mature before fall.

Golden Valley County, MT (Zone 4b) Short season
121 days
Last Spring Frost May 22
121 growing days
First Fall Frost September 20
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Golden Valley County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (33 days to spare)
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: Jul 6 – Aug 10
Recommended (50%) ✓ Fits season (37 days to spare)
Start indoors: Apr 10 Transplant: May 22 🍅 Harvest: Jul 10 – Aug 14
Safe Start (90%) ✓ Fits season (37 days to spare)
Start indoors: Apr 26 Transplant: Jun 7 🍅 Harvest: Jul 26 – Aug 30

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 Golden Valley County

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

Soil pH

Your soil pH (6.8–8.3) is more alkaline than Kohlrabi prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Golden Valley County is excellent for Kohlrabi — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Kohlrabi.

How to Plant Kohlrabi

0.5"
Planting Depth
4"
Between Plants
12"
Between Rows

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

Succession Planting Kohlrabi

3
successive plantings in your 121-day season

Sow every 5.1 weeks. Last sowing by Jul 17 to harvest before frost.

For a dedicated fall crop, sow by Jun 28.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Kohlrabi

Kohlrabi needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Kohlrabi Needs Rainfall You Supplement Action
Jan 2" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 3" 3" 0" ✅ Rainfall sufficient
Jun 3" 1.9" 1.1" 💧 Light watering
Jul 3" 2.3" 0.7" 💧 Light watering
Aug 3" 2.4" 0.6" 💧 Light watering
Sep 3" 1.9" 1.1" 💧 Light watering
Oct 2.4" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Kohlrabi 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.

Kohlrabi needs ~674 GDD — county provides 1,482 GDD Excellent fit

Kohlrabi Planting Timeline — Golden Valley County, MT

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 – Apr 24
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 15 May 15 – Jun 5
Harvest July 10 Jul 10 – Aug 14
Fall Sowing June 28 Jun 28 – Jul 12

Plant 0.5" deep · 4" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

121 days in Golden Valley County

Growing Tips for Kohlrabi in Golden Valley County

Direct sow Kohlrabi outdoors after May 22 in Golden Valley County when soil has warmed and frost danger has passed.

Common pests for Kohlrabi 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 in spring or fall. Harvest when bulbs are 2-3 inches in diameter for best texture and flavor. Larger bulbs may become woody and fibrous.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Kohlrabi in Golden Valley County, MT?

Golden Valley County is in Zone 4b with an average last frost of May 22. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Golden Valley County, MT?

Golden Valley County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 22 and first fall frost is September 20.

🌱

Your Golden Valley County Garden Planner — Free

A 24-page printable planner built for Golden Valley 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 Golden Valley County, MT. 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.