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When to Plant Borage in San Jacinto County, TX

San Jacinto County, Texas Zone 9a May

Your May game plan for San Jacinto County, Texas

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost February 18
Avg. first frost December 1
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Collect borage at their peak

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

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Borage is a self-seeding annual herb with star-shaped blue flowers that attract pollinators. Its leaves have a cucumber-like flavor and the flowers are edible.

San Jacinto County, Texas is in USDA Zone 9a. The average last spring frost is February 18 and the first fall frost is December 1, giving you a growing season of approximately 286 days.

At an elevation of 6 feet, San Jacinto County receives approximately 71.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94°F, providing good warmth for Borage during the growing season. Sandy soil warms quickly in spring — great for early planting — but Borage will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Borage root diseases.

San Jacinto County, TX (Zone 9a) Year-round
286 days
Last Spring Frost February 18
286 growing days
First Fall Frost December 1

San Jacinto County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (189 days to spare)
Start indoors: Jan 13 Transplant: Feb 3 🍅 Harvest: Mar 31 – May 19
Recommended (50%) ✓ Fits season (188 days to spare)
Start indoors: Jan 21 Transplant: Feb 11 🍅 Harvest: Apr 8 – May 27
Safe Start (90%) ✓ Fits season (185 days to spare)
Start indoors: Feb 9 Transplant: Mar 2 🍅 Harvest: Apr 27 – Jun 15

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 San Jacinto County

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

Soil pH

Your soil pH (5.3–6.7) overlaps with Borage's range (6.0–7.0), though not a perfect match.

Soil Texture

Sandy soil in San Jacinto County warms quickly in spring but drains fast. Borage 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 Borage.

How to Plant Borage

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 Borage

6
successive plantings in your 286-day season

Sow every 5.7 weeks. Last sowing by Oct 02 to harvest before frost.

For a dedicated fall crop, sow by Oct 06.

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
Drought risk

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

Monthly Watering Guide for Borage

Borage 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 Borage Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 2.2" 2.5" 0" ✅ Rainfall sufficient
Mar 2.2" 4.2" 0" ✅ Rainfall sufficient
Apr 2.2" 8.5" 0" ✅ Rainfall sufficient
May 2.2" 9.5" 0" ✅ Rainfall sufficient
Jun 2.2" 11.4" 0" ✅ Rainfall sufficient
Jul 2.2" 9.2" 0" ✅ Rainfall sufficient
Aug 2.2" 8" 0" ✅ Rainfall sufficient
Sep 2.2" 6.7" 0" ✅ Rainfall sufficient
Oct 2.2" 5.2" 0" ✅ Rainfall sufficient
Nov 2.2" 2.6" 0" ✅ Rainfall sufficient
Dec 2.2" 1.9" 0.3" 💧 Light watering

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

Borage 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.

Borage needs ~1,128 GDD — county provides 5,883 GDD Excellent fit

Borage Planting Timeline — San Jacinto County, TX

Borage Planting Calendar

Activity When Date Range
Start Indoors January 21 Jan 21 – Feb 4
Transplant Outdoors February 11 Feb 11 – Feb 25
Direct Sow January 28 Jan 28 – Feb 18
Harvest April 8 Apr 8 – May 27
Fall Sowing October 6 Oct 6 – Oct 20

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

50–60 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

286 days in San Jacinto County

Growing Tips for Borage in San Jacinto County

Direct sow Borage outdoors after February 18 in San Jacinto County when soil has warmed and frost danger has passed.

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

With 71" of annual rainfall in San Jacinto County, ensure good drainage for Borage — excess moisture can promote root rot and fungal diseases.

General growing tips

Direct sow in spring as borage does not transplant well. Allow some plants to go to seed for next year. Young leaves are best; older leaves become bristly.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Borage in San Jacinto County, TX?

San Jacinto County is in Zone 9a with an average last frost of February 18. Plan your Borage planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Jacinto County, TX?

San Jacinto County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 18 and first fall frost is December 1.

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Your San Jacinto County Garden Planner — Free

A 24-page printable planner built for San Jacinto 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 San Jacinto 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.