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When to Plant Cilantro in Karnes County, TX

Karnes County, Texas Zone 9a May

Karnes County, Texas gardeners: here's your May plan

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

Avg. last frost February 26
Avg. first frost November 30
Soil temp (4") 59°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. Basket week: cilantro

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

A few tasks this May that'll pay off in June
  • First harvests: cilantro

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Cilantro is a dual-purpose herb providing fresh leaves (cilantro) and dried seeds (coriander). It bolts quickly in heat, producing flowers beloved by beneficial insects.

Karnes County, Texas is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is November 30, giving you a growing season of approximately 277 days.

At an elevation of 4,532 feet, Karnes County receives approximately 67.2 inches of rainfall annually with predominantly loam soil. Summer highs average 95°F, so Cilantro may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Cilantro root diseases.

Karnes County, TX (Zone 9a) Year-round
277 days
Last Spring Frost February 26
277 growing days
First Fall Frost November 30
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Karnes 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 (183 days to spare)
Start indoors: Jan 17 Transplant: Feb 7 🍅 Harvest: Mar 21 – May 23
Recommended (50%) ✓ Fits season (179 days to spare)
Start indoors: Jan 29 Transplant: Feb 19 🍅 Harvest: Apr 2 – Jun 4
Safe Start (90%) ✓ Fits season (175 days to spare)
Start indoors: Feb 23 Transplant: Mar 16 🍅 Harvest: Apr 27 – Jun 29

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 Karnes County

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

Soil pH

Your soil pH (6.3–7.8) is more alkaline than Cilantro prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Cilantro.

Organic Matter

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

How to Plant Cilantro

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

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

Succession Planting Cilantro

8
successive plantings in your 277-day season

Sow every 4.6 weeks. Last sowing by Oct 01 to harvest before frost.

For a dedicated fall crop, sow by Oct 05.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Cilantro

Cilantro needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Cilantro Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 2.2" 2.6" 0" ✅ Rainfall sufficient
Mar 2.2" 4.6" 0" ✅ Rainfall sufficient
Apr 2.2" 6.3" 0" ✅ Rainfall sufficient
May 2.2" 8.6" 0" ✅ Rainfall sufficient
Jun 2.2" 11.7" 0" ✅ Rainfall sufficient
Jul 2.2" 9.1" 0" ✅ Rainfall sufficient
Aug 2.2" 8.7" 0" ✅ Rainfall sufficient
Sep 2.2" 6.7" 0" ✅ Rainfall sufficient
Oct 2.2" 3.9" 0" ✅ Rainfall sufficient
Nov 2.2" 2" 0.2" 💧 Light watering
Dec 1.5" 0" ❄️ Dormant

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

Cilantro 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.

Cilantro needs ~1,062 GDD — county provides 5,907 GDD Excellent fit

Cilantro Planting Timeline — Karnes County, TX

Cilantro Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 – Feb 12
Transplant Outdoors February 19 Feb 19 – Mar 5
Direct Sow February 5 Feb 5 – Feb 26
Harvest April 2 Apr 2 – Jun 4
Fall Sowing October 5 Oct 5 – Oct 19

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

277 days in Karnes County

Growing Tips for Cilantro in Karnes County

Direct sow Cilantro outdoors after February 26 in Karnes County when soil has warmed and frost danger has passed.

Summer highs in Karnes County reach 95°F — grow Cilantro as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 278.0-day season in Karnes County allows multiple plantings of Cilantro. Sow every 20.0 days for continuous harvest.

Common pests for Cilantro in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

With 67" of annual rainfall in Karnes County, ensure good drainage for Cilantro — excess moisture can promote root rot and fungal diseases.

General growing tips

Succession sow every 2-3 weeks. Provide afternoon shade in warm weather. Harvest leaves before flowering or allow some plants to go to seed for coriander and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cilantro in Karnes County, TX?

Karnes County is in Zone 9a with an average last frost of February 26. Plan your Cilantro planting based on this frost date — see the calendar above for exact timing.

What planting zone is Karnes County, TX?

Karnes County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is November 30.

🌱

Your Karnes County Garden Planner — Free

A 24-page printable planner built for Karnes 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 Karnes 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.