When to Plant Marigolds in Harris County, TX
Harris County, Texas gardeners: here's your August plan
Your Harris County, Texas garden is entering a new phase. Here's what's on the schedule for August and why each task matters now.
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It's harvest week for marigolds
If you can't use it all right away, check the food-preservation section of your planner.
September will be here before you know it — start on
- First harvests: marigolds
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.
Harris County, Texas is in USDA Zone 9b. The average last spring frost is February 14 and the first fall frost is December 4, giving you a growing season of approximately 293 days.
At an elevation of 390 feet, Harris County receives approximately 67.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 102°F, so Marigolds may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Marigolds will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Marigolds root diseases.
Harris County Soil Profile
Soil Type
Sandy Loam
Soil pH
5.3-6.5
Drainage
Well Drained
Marigolds Planting Risk Windows
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 Harris County
How your county's soil matches Marigolds's growing requirements.
Soil pH
Your soil pH (5.3–6.5) is more acidic than Marigolds prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
Sandy soil in Harris County warms quickly in spring but drains fast. Marigolds 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 Marigolds.
How to Plant Marigolds
Succession Planting Marigolds
Sow every 5.7 weeks. Last sowing by Sep 25 to harvest before frost.
Marigolds Water Budget
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 | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| Mar | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 7.4" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 10.1" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 10" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 9.6" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 8.5" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 6.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Dec | 2.2" | 1.6" | 0.6" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in Harris 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 Planting Timeline — Harris County, TX
Marigolds Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 10 | Jan 10 – Jan 24 |
| Transplant Outdoors | January 24 | Jan 24 – Feb 7 |
| Direct Sow | January 24 | Jan 24 – Feb 14 |
| Bloom | March 21 | Mar 21 – Sep 12 |
Plant 0.3" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Transplant Outdoors Direct Sow |
| February | Transplant Outdoors Direct Sow |
| March | Bloom |
| 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_acidic
🗺️ USDA Zone
Zone 9b
📆 Growing Season
293 days in Harris County
Growing Tips for Marigolds in Harris County
Direct sow Marigolds outdoors after February 14 in Harris County when soil has warmed and frost danger has passed.
Sandy soil in Harris County dries quickly — mulch Marigolds with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 102°F in Harris County, provide afternoon shade for Marigolds and water deeply in the morning.
Common pests for Marigolds in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
With 68" of annual rainfall in Harris 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
Check more plant combinations with our Companion Planting Checker →
Very easy to save. Seeds are the long, thin, dark pieces inside the dried flower head.
Marigolds in Other Locations
Frequently Asked Questions
When should I plant Marigolds in Harris County, TX?
Harris County is in Zone 9b with an average last frost of February 14. Plan your Marigolds planting based on this frost date — see the calendar above for exact timing.
What planting zone is Harris County, TX?
Harris County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 14 and first fall frost is December 4.
Your Harris County Garden Planner — Free
A 22-page printable planner built for Harris County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.