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When to Plant Kohlrabi in Palm Beach County, FL

Palm Beach County, Florida Zone 10b May

Your May game plan for Palm Beach County, Florida

Welcome to May in Zone 10b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 17
Soil temp (4") 81°F
Watering Moderate
Pest pressure High
Daylight 13.3 hrs
  1. Collect kohlrabi at their peak

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

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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.

Palm Beach County, Florida is in USDA Zone 10b. The average last spring frost is February 17 and the first fall frost is April 15, giving you a growing season of approximately 57 days.

At an elevation of 355 feet, Palm Beach County receives approximately 50 inches of rainfall annually with predominantly sand soil. Summer highs average 93°F, providing good warmth for Kohlrabi during the growing season. Sandy soil warms quickly in spring — great for early planting — but Kohlrabi will need more frequent watering and organic matter to retain nutrients.

Palm Beach County, FL (Zone 10b) Very short season
57 days
Last Spring Frost February 17
57 growing days
First Fall Frost April 15
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Palm Beach County Soil Profile

Soil Type

Sand

Soil pH

5.1-5.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (163 days to spare)
Start indoors: Jan 13 Transplant: Feb 10 🍅 Harvest: Mar 31 – May 5
Recommended (50%) ✓ Fits season (156 days to spare)
Start indoors: Jan 20 Transplant: Feb 17 🍅 Harvest: Apr 7 – May 12
Safe Start (90%) ✓ Fits season (149 days to spare)
Start indoors: Jan 27 Transplant: Feb 24 🍅 Harvest: Apr 14 – May 19

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 Palm Beach County

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

Soil pH

Your soil pH (5.1–5.9) is more acidic than Kohlrabi prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Palm Beach County warms quickly in spring but drains fast. Kohlrabi will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Kohlrabi.

Organic Matter

Organic matter is low (1.3%). Add 2-3 inches of compost before planting Kohlrabi.

How to Plant Kohlrabi

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

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 1,087 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 2.4" 0" ❄️ Dormant
Feb 3" 2.3" 0.7" 💧 Light watering
Mar 3" 3.2" 0" ✅ Rainfall sufficient
Apr 3" 2.4" 0.6" 💧 Light watering
May 3" 3.3" 0" ✅ Rainfall sufficient
Jun 3" 6.2" 0" ✅ Rainfall sufficient
Jul 3" 7.3" 0" ✅ Rainfall sufficient
Aug 3" 7.4" 0" ✅ Rainfall sufficient
Sep 3" 7" 0" ✅ Rainfall sufficient
Oct 3" 4.2" 0" ✅ Rainfall sufficient
Nov 2" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Oct in Palm Beach 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 ~1,086 GDD — county provides 7,208 GDD Excellent fit

Kohlrabi Planting Timeline — Palm Beach County, FL

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors January 20 Jan 20 – Feb 3
Transplant Outdoors February 17 Feb 17 – Mar 3
Direct Sow January 27 Jan 27 – Feb 17
Harvest April 7 Apr 7 – May 12
Fall Sowing February 18 Feb 18 – Mar 4

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · 1-2 times/week

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 10b

📆 Growing Season

57 days in Palm Beach County

Growing Tips for Kohlrabi in Palm Beach County

Direct sow Kohlrabi outdoors after February 17 in Palm Beach County when soil has warmed and frost danger has passed.

Sandy soil in Palm Beach County dries quickly — mulch Kohlrabi with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Your generous 365.0-day season in Palm Beach 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 Palm Beach County, FL?

Palm Beach County is in Zone 10b with an average last frost of February 17. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Palm Beach County, FL?

Palm Beach County, Florida is in USDA Hardiness Zone 10b. The average last spring frost is February 17 and first fall frost is .

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Your Palm Beach County Garden Planner — Free

A 24-page printable planner built for Palm Beach County (Zone 10b). 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 Palm Beach County, FL. 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.