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When to Plant Kohlrabi in Kitsap County, WA

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.

Kitsap County, Washington is in USDA Zone 8a. The average last spring frost is March 25 and the first fall frost is November 5, giving you a growing season of approximately 225 days.

At an elevation of 264 feet, Kitsap County receives approximately 38 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Kohlrabi during the growing season.

Kitsap County, WA (Zone 8a) Long season
225 days
Last Spring Frost March 25
225 growing days
First Fall Frost November 5

Kitsap County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (139 days to spare)
Start indoors: Feb 13 Transplant: Mar 20 🍅 Harvest: May 8 – Jun 12
Recommended (50%) ✓ Fits season (141 days to spare)
Start indoors: Feb 18 Transplant: Mar 25 🍅 Harvest: May 13 – Jun 17
Safe Start (90%) ✓ Fits season (143 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jun 3 – Jul 8

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 Kitsap County

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

Soil pH

Your soil pH (5.3โ€“6.3) is more acidic than Kohlrabi prefers (6.0โ€“7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Kitsap County is excellent for Kohlrabi โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.5%) โ€” Kohlrabi will thrive.

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

6
successive plantings in your 225-day season

Sow every 5.1 weeks. Last sowing by Sep 01 to harvest before frost.

For a dedicated fall crop, sow by Aug 27.

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

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 โ€” 5.1" 0" โ„๏ธ Dormant
Feb โ€” 4.5" 0" โ„๏ธ Dormant
Mar 3" 4.3" 0" โœ… Rainfall sufficient
Apr 3" 2.7" 0.3" ๐Ÿ’ง Light watering
May 3" 2" 1" ๐Ÿ’ง Light watering
Jun 3" 1.3" 1.7" ๐Ÿšฟ Regular watering
Jul 3" 0.7" 2.3" ๐Ÿšฟ Regular watering
Aug 3" 0.7" 2.3" ๐Ÿšฟ Regular watering
Sep 3" 1.4" 1.6" ๐Ÿšฟ Regular watering
Oct 3" 2.9" 0.1" ๐Ÿ’ง Light watering
Nov 3" 6.5" 0" โœ… Rainfall sufficient
Dec โ€” 6" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Kitsap County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~756 GDD — county provides 3,093 GDD Excellent fit

Kohlrabi Planting Timeline โ€” Kitsap County, WA

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 โ€“ Mar 4
Transplant Outdoors March 25 Mar 25 โ€“ Apr 8
Direct Sow March 11 Mar 11 โ€“ Apr 1
Harvest May 13 May 13 โ€“ Jun 17
Fall Sowing August 27 Aug 27 โ€“ Sep 10

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.7"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

45โ€“65 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

225 days in Kitsap County

Growing Tips for Kohlrabi in Kitsap County

Direct sow Kohlrabi outdoors after March 25 in Kitsap County when soil has warmed and frost danger has passed.

Your generous 225.0-day season in Kitsap County allows multiple plantings of Kohlrabi. Sow every 22.0 days for continuous harvest.

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 Kitsap County, WA?

Kitsap County is in Zone 8a with an average last frost of March 25. Plan your Kohlrabi planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Kitsap County, WA?

Kitsap County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is March 25 and first fall frost is November 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Kitsap County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Kitsap County, WA. Local conditions may vary. Last updated: April 2026.