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When to Plant Calendula in Willacy County, TX

Willacy County, Texas Zone 10a August

August to-do list for Willacy County, Texas

Your garden in Willacy County, Texas is working on a schedule, even when you're not. Here's where you should be this August.

Avg. last frost February 4
Avg. first frost December 22
Soil temp (4") 97°F
Watering Low
Pest pressure High
Daylight 12.9 hrs
  1. Plant fall tomatoes & peppers

    Late August is your fall transplant window. Pick heat-tolerant determinate tomatoes (Heatmaster, Solar Fire, Phoenix). They'll set fruit through fall.

  2. Direct-sow brassicas indoors or in shade

    Broccoli, cauliflower, cabbage, Brussels sprouts germinate better in cooler conditions. Start indoors or under shade cloth, transplant in September.

  3. Refresh mulch & drip lines

    Check drip irrigation for clogs (afternoon thunderstorm grit). Top off mulch in all beds before the cool-season crops go in.

A few tasks this August that'll pay off in September
  • Fall sowing: 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.

Willacy County, Texas is in USDA Zone 10a. The average last spring frost is February 4 and the first fall frost is December 22, giving you a growing season of approximately 321 days.

At an elevation of 1,085 feet, Willacy County receives approximately 65.9 inches of rainfall annually with predominantly loam soil. Summer highs average 102°F, so Calendula may need afternoon shade and extra watering during peak heat. 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
Willacy County, TX (Zone 10a) Year-round
321 days
Last Spring Frost February 4
321 growing days
First Fall Frost December 22

Willacy County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.3

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (235 days to spare)
Transplant: Dec 6 🌸 Bloom: Jan 17 – Apr 25
Recommended (50%) ✓ Fits season (223 days to spare)
Transplant: Dec 24 🌸 Bloom: Feb 4 – May 13
Safe Start (90%) ✓ Fits season (200 days to spare)
Transplant: Jan 21 🌸 Bloom: Mar 4 – Jun 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 Willacy County

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

Soil pH

Your soil pH (6.5–7.3) overlaps with Calendula's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Calendula.

Organic Matter

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

How to Plant Calendula

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

Fall planting: Sow 14 weeks before your first frost date for a fall harvest.

Succession Planting Calendula

7
successive plantings in your 321-day season

Sow every 5.7 weeks. Last sowing by Oct 13 to harvest before frost.

For a dedicated fall crop, sow by Sep 15.

Calendula Water Budget

Plant needs
0.5″/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 — 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" 2.3" 0" ✅ Rainfall sufficient
Mar 2.2" 4.4" 0" ✅ Rainfall sufficient
Apr 2.2" 6.4" 0" ✅ Rainfall sufficient
May 2.2" 9.5" 0" ✅ Rainfall sufficient
Jun 2.2" 9.7" 0" ✅ Rainfall sufficient
Jul 2.2" 9" 0" ✅ Rainfall sufficient
Aug 2.2" 8.5" 0" ✅ Rainfall sufficient
Sep 2.2" 6.3" 0" ✅ Rainfall sufficient
Oct 2.2" 3.8" 0" ✅ Rainfall sufficient
Nov 2.2" 2.6" 0" ✅ Rainfall sufficient
Dec 2.2" 1.8" 0.4" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in Willacy 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 ~1,590 GDD — county provides 8,533 GDD Excellent fit

Calendula Planting Timeline — Willacy County, TX

Calendula Planting Calendar

Activity When Date Range
Transplant Outdoors December 24 Dec 24 – Jan 7
Direct Sow November 26 Nov 26 – Dec 17
Bloom February 4 Feb 4 – May 13
Fall Sowing September 15 Sep 15 – Sep 29

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

Month-by-Month Timeline

MonthActivities
January Transplant Outdoors
February Bloom
March Bloom
April Bloom
May Bloom
June
July
August
September Fall Sowing
October
November Direct Sow
December Transplant Outdoors 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 10a

📆 Growing Season

321 days in Willacy County

Growing Tips for Calendula in Willacy County

Direct sow Calendula outdoors after February 04 in Willacy County when soil has warmed and frost danger has passed.

With summer highs reaching 102°F in Willacy County, provide afternoon shade for Calendula and water deeply in the morning.

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 Willacy County, TX?

Willacy County is in Zone 10a with an average last frost of February 4. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Willacy County, TX?

Willacy County, Texas is in USDA Hardiness Zone 10a. The average last spring frost is February 4 and first fall frost is December 22.

🌱

Your Willacy County Garden Planner — Free

A 22-page printable planner built for Willacy County (Zone 10a). 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 Willacy County, TX. Local conditions may vary. Last updated: August 2026.

Sources & credits

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