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When to Plant Kohlrabi in Owyhee County, ID

Owyhee County, Idaho Zone 7a May

What to do in May

Each item below is timed to Owyhee County, Idaho's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost June 9
Avg. first frost September 20
Soil temp (4") 51°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
  1. Scatter kohlrabi into prepared beds

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

June will be here before you know it — start on
  • Transplants going out: 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.

Owyhee County, Idaho is in USDA Zone 7a. The average last spring frost is June 9 and the first fall frost is September 20, giving you a growing season of approximately 103 days.

At an elevation of 4,621 feet, Owyhee County receives approximately 18.1 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Kohlrabi during the growing season. With low rainfall, drip irrigation is essential for growing Kohlrabi successfully. Mulch heavily to conserve soil moisture.

Owyhee County, ID (Zone 7a) Short season
103 days
Last Spring Frost June 9
103 growing days
First Fall Frost September 20

Owyhee County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (20 days to spare)
Start indoors: Apr 27 Transplant: Jun 1 🍅 Harvest: Jul 20 – Aug 24
Recommended (50%) ✓ Fits season (19 days to spare)
Start indoors: May 5 Transplant: Jun 9 🍅 Harvest: Jul 28 – Sep 1
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: May 15 Transplant: Jun 19 🍅 Harvest: Aug 7 – Sep 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 Owyhee County

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

Soil pH

Your soil pH (6.3–7.8) overlaps with Kohlrabi's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Kohlrabi.

How to Plant Kohlrabi

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Kohlrabi

2
successive plantings in your 103-day season

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

For a dedicated fall crop, sow by Jul 12.

Plant Water Budget

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

Water stress score is 8/10 — 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 1.1" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.3" 0" ❄️ Dormant
Jun 3" 1.4" 1.6" 🚿 Regular watering
Jul 3" 1.8" 1.2" 💧 Light watering
Aug 3" 1.7" 1.3" 💧 Light watering
Sep 3" 1.3" 1.7" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Owyhee 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 ~962 GDD — county provides 1,802 GDD Excellent fit

Kohlrabi Planting Timeline — Owyhee County, ID

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors May 5 May 5 – May 19
Transplant Outdoors June 9 Jun 9 – Jun 23
Direct Sow May 26 May 26 – Jun 16
Harvest July 28 Jul 28 – Sep 1
Fall Sowing July 12 Jul 12 – Jul 26

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

Month-by-Month Timeline

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

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: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

103 days in Owyhee County

Growing Tips for Kohlrabi in Owyhee County

Direct sow Kohlrabi outdoors after June 09 in Owyhee 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 Owyhee County, ID?

Owyhee County is in Zone 7a with an average last frost of June 9. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Owyhee County, ID?

Owyhee County, Idaho is in USDA Hardiness Zone 7a. The average last spring frost is June 9 and first fall frost is September 20.

🌱

Your Owyhee County Garden Planner — Free

A 24-page printable planner built for Owyhee County (Zone 7a). 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 Owyhee County, ID. 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.