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When to Plant Basil in Jefferson County, TX

Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.

Jefferson County, Texas is in USDA Zone 9a. The average last spring frost is February 13 and the first fall frost is December 6, giving you a growing season of approximately 296 days.

At an elevation of 349 feet, Jefferson County receives approximately 64.9 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 101ยฐF, so Basil may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Basil will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Basil root diseases.

Jefferson County, TX (Zone 9a) Year-round
296 days
Last Spring Frost February 13
296 growing days
First Fall Frost December 6

Jefferson County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.4-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (182 days to spare)
Start indoors: Dec 13 Transplant: Jan 31 🍅 Harvest: Mar 28 – May 30
Recommended (50%) ✓ Fits season (170 days to spare)
Start indoors: Jan 2 Transplant: Feb 20 🍅 Harvest: Apr 17 – Jun 19
Safe Start (90%) ✓ Fits season (167 days to spare)
Start indoors: Jan 23 Transplant: Mar 13 🍅 Harvest: May 8 – Jul 10

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 Jefferson County

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

Soil pH

Your soil pH (5.4โ€“6.5) is more acidic than Basil prefers (6.0โ€“7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

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

How to Plant Basil

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

Succession Planting Basil

7
successive plantings in your 296-day season

Sow every 5.7 weeks. Last sowing by Sep 22 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Basil

Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Basil Needs Rainfall You Supplement Action
Jan โ€” 1.6" 0" โ„๏ธ Dormant
Feb 2.6" 2.1" 0.5" ๐Ÿ’ง Light watering
Mar 2.6" 4.4" 0" โœ… Rainfall sufficient
Apr 2.6" 6.3" 0" โœ… Rainfall sufficient
May 2.6" 9.8" 0" โœ… Rainfall sufficient
Jun 2.6" 10.7" 0" โœ… Rainfall sufficient
Jul 2.6" 8.8" 0" โœ… Rainfall sufficient
Aug 2.6" 6.6" 0" โœ… Rainfall sufficient
Sep 2.6" 6.6" 0" โœ… Rainfall sufficient
Oct 2.6" 4.4" 0" โœ… Rainfall sufficient
Nov 2.6" 2.1" 0.5" ๐Ÿ’ง Light watering
Dec 2.6" 1.6" 1" ๐Ÿ’ง Light watering

Water needs are for active growing months only (Febโ€“Dec in Jefferson County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Basil 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.

Basil needs ~1,609 GDD — county provides 7,647 GDD Excellent fit

Basil Planting Timeline โ€” Jefferson County, TX

Basil Planting Calendar

Activity When Date Range
Start Indoors January 2 Jan 2 โ€“ Jan 16
Transplant Outdoors February 20 Feb 20 โ€“ Mar 6
Direct Sow February 20 Feb 20 โ€“ Mar 13
Harvest April 17 Apr 17 โ€“ Jun 19

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.6"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

50โ€“75 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 9a

๐Ÿ“† Growing Season

296 days in Jefferson County

Growing Tips for Basil in Jefferson County

Direct sow Basil outdoors after February 13 in Jefferson County when soil has warmed and frost danger has passed.

Sandy soil in Jefferson County dries quickly โ€” mulch Basil with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 101ยฐF in Jefferson County, provide afternoon shade for Basil and water deeply in the morning.

General growing tips

Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.

Recommended Basil Varieties for Jefferson County

Downy mildew-resistant basil for your humid climate

Prospera (DM-resistant) Amazel Eleonora

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

๐ŸŒพ Save Your Own Basil Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower spikes dry brown on the plant.
Storage Store airtight; viable 5 years at 35ยฐF, under 45% humidity.

Isolate 150 ft between varieties. Different basil species can cross.

Frequently Asked Questions

When should I plant Basil in Jefferson County, TX?

Jefferson County is in Zone 9a with an average last frost of February 13. Plan your Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jefferson County, TX?

Jefferson County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 13 and first fall frost is December 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jefferson County gardeners in Zone 9a 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 Jefferson County, TX. Local conditions may vary. Last updated: April 2026.