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When to Plant Eggplant in Starr County, TX

Starr County, Texas Zone 9b May

May to-do list for Starr County, Texas

Here's what deserves your attention in Starr County, Texas this month. Everything below is tailored to Zone 9b and timed around your local frost dates.

Avg. last frost February 3
Avg. first frost December 16
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.3 hrs
  1. Bring in the eggplant

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Looking ahead to June
  • First harvests: eggplant

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Eggplant is a heat-loving solanaceous crop that produces glossy fruits in purple, white, or striped varieties. It requires long, warm growing seasons for best production.

Starr County, Texas is in USDA Zone 9b. The average last spring frost is February 3 and the first fall frost is December 16, giving you a growing season of approximately 316 days.

At an elevation of 2,451 feet, Starr County receives approximately 55.4 inches of rainfall annually with predominantly loam soil. Summer highs average 98°F, so Eggplant may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Eggplant root diseases.

Starr County, TX (Zone 9b) Year-round
316 days
Last Spring Frost February 3
316 growing days
First Fall Frost December 16

Starr County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (186 days to spare)
Start indoors: Dec 7 Transplant: Jan 25 🍅 Harvest: Apr 5 – Jun 7
Recommended (50%) ✓ Fits season (176 days to spare)
Start indoors: Dec 23 Transplant: Feb 10 🍅 Harvest: Apr 21 – Jun 23
Safe Start (90%) ✓ Fits season (157 days to spare)
Start indoors: Jan 20 Transplant: Mar 10 🍅 Harvest: May 19 – Jul 21

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 Starr County

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

Soil pH

Your soil pH (6.8–7.5) is more alkaline than Eggplant prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Eggplant.

How to Plant Eggplant

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Eggplant

5
successive plantings in your 316-day season

Sow every 7.4 weeks. Last sowing by Sep 22 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 1,239 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Eggplant

Eggplant needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.

Month Eggplant Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 4.8" 1.9" 2.9" 🚿 Regular watering
Mar 4.8" 3.4" 1.4" 💧 Light watering
Apr 4.8" 6.6" 0" ✅ Rainfall sufficient
May 4.8" 8.8" 0" ✅ Rainfall sufficient
Jun 4.8" 7.6" 0" ✅ Rainfall sufficient
Jul 4.8" 7" 0" ✅ Rainfall sufficient
Aug 4.8" 6.4" 0" ✅ Rainfall sufficient
Sep 4.8" 4.9" 0" ✅ Rainfall sufficient
Oct 4.8" 4" 0.8" 💧 Light watering
Nov 4.8" 1.6" 3.2" 🚿 Regular watering
Dec 4.8" 1.6" 3.2" 🚿 Regular watering

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

Eggplant 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.

Eggplant needs ~1,762 GDD — county provides 7,449 GDD Excellent fit

Eggplant Planting Timeline — Starr County, TX

Eggplant Planting Calendar

Activity When Date Range
Start Indoors December 23 Dec 23 – Jan 6
Transplant Outdoors February 10 Feb 10 – Feb 24
Direct Sow February 3 Feb 3 – Feb 24
Harvest April 21 Apr 21 – Jun 23

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · 1-2 times/week

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

316 days in Starr County

Growing Tips for Eggplant in Starr County

Direct sow Eggplant outdoors after February 03 in Starr County when soil has warmed and frost danger has passed.

With summer highs reaching 98°F in Starr County, provide afternoon shade for Eggplant and water deeply in the morning.

Common pests for Eggplant in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 8-10 weeks before last frost. Transplant only after nighttime temperatures stay above 55F. Mulch to retain moisture and warmth around roots.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
  • Kohlrabi

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Eggplant in Starr County, TX?

Starr County is in Zone 9b with an average last frost of February 3. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Starr County, TX?

Starr County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 3 and first fall frost is December 16.

🌱

Your Starr County Garden Planner — Free

A 24-page printable planner built for Starr County (Zone 9b). 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 Starr 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.