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When to Plant Marigolds in Washington County, TX

Washington County, Texas Zone 9a July

Washington County, Texas gardeners: here's your July plan

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

Avg. last frost March 2
Avg. first frost November 27
Soil temp (4") 89°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Collect marigolds at their peak

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

August will be here before you know it — start on
  • First harvests: marigolds

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Marigolds (Tagetes patula) are warm-season annuals beloved for their cheerful orange, yellow, and red blooms — and for their well-documented ability to repel pest nematodes in vegetable beds. Easy from seed, drought-tolerant once established, and bloom from early summer until the first hard frost.

Washington County, Texas is in USDA Zone 9a. The average last spring frost is March 2 and the first fall frost is November 27, giving you a growing season of approximately 270 days.

At an elevation of 386 feet, Washington County receives approximately 58.9 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, providing good warmth for Marigolds during the growing season. Clay soil retains moisture well for Marigolds, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Marigolds root diseases.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Washington County, TX (Zone 9a) Year-round
270 days
Last Spring Frost March 2
270 growing days
First Fall Frost November 27

Washington County Soil Profile

Soil Type

Clay

Soil pH

6.9-8.4

Drainage

Well Drained

Marigolds Planting Risk Windows

Early Start (70% safe) ✓ Fits season (77 days to spare)
Start indoors: Jan 11 Transplant: Feb 1 🌸 Bloom: Mar 29 – Aug 30
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Jan 26 Transplant: Feb 16 🌸 Bloom: Apr 13 – Sep 14
Safe Start (90%) ✓ Fits season (75 days to spare)
Start indoors: Feb 15 Transplant: Mar 8 🌸 Bloom: May 3 – Oct 4

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 Washington County

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

Soil pH

Your soil pH (6.9–8.4) is more alkaline than Marigolds prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Your clay soil in Washington County is workable for Marigolds. Add compost annually to improve structure.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Marigolds.

How to Plant Marigolds

0.3"
Planting Depth
10"
Between Plants
12"
Between Rows

Succession Planting Marigolds

6
successive plantings in your 270-day season

Sow every 5.7 weeks. Last sowing by Sep 18 to harvest before frost.

Marigolds Water Budget

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

Monthly Watering Guide for Marigolds

Marigolds 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 Marigolds Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.2" 4.3" 0" ✅ Rainfall sufficient
Apr 2.2" 5.8" 0" ✅ Rainfall sufficient
May 2.2" 8.3" 0" ✅ Rainfall sufficient
Jun 2.2" 9.9" 0" ✅ Rainfall sufficient
Jul 2.2" 7" 0" ✅ Rainfall sufficient
Aug 2.2" 7.4" 0" ✅ Rainfall sufficient
Sep 2.2" 5.2" 0" ✅ Rainfall sufficient
Oct 2.2" 4.2" 0" ✅ Rainfall sufficient
Nov 2.2" 2" 0.2" 💧 Light watering
Dec 1.4" 0" ❄️ Dormant

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

Marigolds 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.

Marigolds needs ~1,050 GDD — county provides 4,725 GDD Excellent fit

Marigolds Planting Timeline — Washington County, TX

Marigolds Planting Calendar

Activity When Date Range
Start Indoors January 26 Jan 26 – Feb 9
Transplant Outdoors February 16 Feb 16 – Mar 2
Direct Sow February 16 Feb 16 – Mar 9
Bloom April 13 Apr 13 – Sep 14

Plant 0.3" deep · 10" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

270 days in Washington County

Growing Tips for Marigolds in Washington County

Direct sow Marigolds outdoors after March 02 in Washington County when soil has warmed and frost danger has passed.

With Washington County's clay soil (37% clay), work in 3-4 inches of compost before planting Marigolds. Avoid tilling when soil is wet to prevent compaction.

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

With 59" of annual rainfall in Washington County, ensure good drainage for Marigolds — excess moisture can promote root rot and fungal diseases.

General growing tips

Direct-sow after last frost or start indoors 4-6 weeks earlier. Deadhead spent blooms to keep new flowers coming. French marigolds (T. patula) are the most reliable nematode repellents — plant a band around vegetable beds. Tolerate poor soil but bloom best with monthly compost.

Companion Planting

Good Companions

Avoid Planting Near

  • Beans
  • Cabbage

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Marigolds Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower heads dry on plant. Pull dried petals to reveal seeds.
Storage Store in envelopes; viable 3 years at 35°F, under 50% humidity.

Very easy to save. Seeds are the long, thin, dark pieces inside the dried flower head.

Frequently Asked Questions

When should I plant Marigolds in Washington County, TX?

Washington County is in Zone 9a with an average last frost of March 2. Plan your Marigolds planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, TX?

Washington County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 2 and first fall frost is November 27.

🌱

Your Washington County Garden Planner — Free

A 22-page printable planner built for Washington 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Washington County, TX. Local conditions may vary. Last updated: July 2026.

Sources & credits

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