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When to Plant Kohlrabi in Hays County, TX

Hays County, Texas Zone 9a May

Your May planting checklist for Hays County, Texas

We've pulled the most time-sensitive tasks for Hays County, Texas this May and put them front and centre. Tackle them in order.

Avg. last frost March 6
Avg. first frost November 22
Soil temp (4") 66°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Pick kohlrabi

    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.

Hays County, Texas is in USDA Zone 9a. The average last spring frost is March 6 and the first fall frost is November 22, giving you a growing season of approximately 261 days.

At an elevation of 3,119 feet, Hays County receives approximately 61.8 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, providing good warmth for Kohlrabi during the growing season. Clay soil retains moisture well for Kohlrabi, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Kohlrabi root diseases.

Hays County, TX (Zone 9a) Long season
261 days
Last Spring Frost March 6
261 growing days
First Fall Frost November 22

Hays County Soil Profile

Soil Type

Clay

Soil pH

7-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (179 days to spare)
Start indoors: Jan 27 Transplant: Feb 24 🍅 Harvest: Apr 14 – May 19
Recommended (50%) ✓ Fits season (177 days to spare)
Start indoors: Feb 6 Transplant: Mar 6 🍅 Harvest: Apr 24 – May 29
Safe Start (90%) ✓ Fits season (169 days to spare)
Start indoors: Mar 5 Transplant: Apr 2 🍅 Harvest: May 21 – Jun 25

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 Hays County

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

Soil pH

Your soil pH (7.0–8.0) overlaps with Kohlrabi's range (6.0–7.5), though not a perfect match.

Soil Texture

Heavy clay soil (45% clay) in Hays County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help 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.

Succession Planting Kohlrabi

7
successive plantings in your 261-day season

Sow every 5.1 weeks. Last sowing by Sep 18 to harvest before frost.

For a dedicated fall crop, sow by Sep 27.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.0″/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 1.6" 0" ❄️ Dormant
Feb 2.3" 0" ❄️ Dormant
Mar 3" 3.5" 0" ✅ Rainfall sufficient
Apr 3" 6.5" 0" ✅ Rainfall sufficient
May 3" 9.5" 0" ✅ Rainfall sufficient
Jun 3" 9.8" 0" ✅ Rainfall sufficient
Jul 3" 7" 0" ✅ Rainfall sufficient
Aug 3" 8.1" 0" ✅ Rainfall sufficient
Sep 3" 5.1" 0" ✅ Rainfall sufficient
Oct 3" 4.2" 0" ✅ Rainfall sufficient
Nov 3" 2.3" 0.7" 💧 Light watering
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Hays 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 4,567 GDD Excellent fit

Kohlrabi Planting Timeline — Hays County, TX

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors February 6 Feb 6 – Feb 20
Transplant Outdoors March 6 Mar 6 – Mar 20
Direct Sow February 13 Feb 13 – Mar 6
Harvest April 24 Apr 24 – May 29
Fall Sowing September 27 Sep 27 – Oct 11

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors Direct Sow
March Transplant Outdoors Direct Sow
April Harvest
May Harvest
June
July
August
September Fall Sowing
October Fall Sowing
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 9a

📆 Growing Season

261 days in Hays County

Growing Tips for Kohlrabi in Hays County

Direct sow Kohlrabi outdoors after March 06 in Hays County when soil has warmed and frost danger has passed.

With Hays County's clay soil (45% clay), work in 3-4 inches of compost before planting Kohlrabi. Avoid tilling when soil is wet to prevent compaction.

Your generous 261.0-day season in Hays 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 Hays County, TX?

Hays County is in Zone 9a with an average last frost of March 6. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hays County, TX?

Hays County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 6 and first fall frost is November 22.

🌱

Your Hays County Garden Planner — Free

A 24-page printable planner built for Hays County (Zone 9a). 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 Hays County, TX. 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.