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When to Plant Calendula in San Jacinto County, TX

San Jacinto County, Texas Zone 9a June

This month in San Jacinto County, Texas

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

Avg. last frost February 18
Avg. first frost December 1
Soil temp (4") 82°F
Watering Low
Pest pressure High
Daylight 14 hrs
  1. It's harvest week for calendula

    If you can't use it all right away, check the food-preservation section of your planner.

A few tasks this June that'll pay off in July
  • First harvests: calendula

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Calendula (Calendula officinalis) is a cheerful, edible-flowered cool-season annual valued by herbalists, chefs, and gardeners alike. Its golden-orange petals are used in salves, teas, and as a saffron substitute. Hardy enough to tolerate light frosts, it blooms prolifically in spring and fall, taking a pause during the hottest weeks of summer.

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 Calendula during the growing season. Sandy soil warms quickly in spring — great for early planting — but Calendula will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Calendula root diseases.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
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

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (147 days to spare)
Transplant: Jan 13 🌸 Bloom: Feb 24 – Jun 30
Recommended (50%) ✓ Fits season (146 days to spare)
Transplant: Jan 21 🌸 Bloom: Mar 4 – Jul 8
Safe Start (90%) ✓ Fits season (143 days to spare)
Transplant: Feb 9 🌸 Bloom: Mar 23 – Jul 27

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 Calendula's growing requirements.

Soil pH

Your soil pH (5.3–6.7) overlaps with Calendula's range (5.5–7.0), though not a perfect match.

Soil Texture

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

How to Plant Calendula

0.3"
Planting Depth
9"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Calendula

6
successive plantings in your 286-day season

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

For a dedicated fall crop, sow by Sep 08.

Calendula 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 Calendula

Calendula 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 Calendula 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.

Calendula 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.

Calendula needs ~1,230 GDD — county provides 5,883 GDD Excellent fit

Calendula Planting Timeline — San Jacinto County, TX

Calendula Planting Calendar

Activity When Date Range
Transplant Outdoors January 21 Jan 21 – Feb 4
Direct Sow December 24 Dec 24 – Jan 14
Bloom March 4 Mar 4 – Jul 8
Fall Sowing September 8 Sep 8 – Sep 22

Plant 0.3" deep · 9" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

286 days in San Jacinto County

Growing Tips for Calendula in San Jacinto County

Direct sow Calendula 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 Calendula with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Common pests for Calendula in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct-sow in early spring as soon as soil can be worked — seeds germinate in cool soil (50-65°F). In zones 7+, also sow in fall for winter/spring bloom. Deadhead consistently to extend bloom. Plants self-seed readily; save a few spent heads and allow them to drop. Harvest petals when flowers are fully open for best flavor and medicinal value.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

San Jacinto County is in Zone 9a with an average last frost of February 18. Plan your Calendula 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.

🌱

Your San Jacinto County Garden Planner — Free

A 22-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: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.