When to Plant Marigolds in King County, TX
May in the garden — King County, Texas
A quick May briefing for King County, Texas gardeners — what's urgent, what's next, and what can wait.
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Bring in the marigolds
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
Before June arrives, get these ready
- 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.
King County, Texas is in USDA Zone 8a. The average last spring frost is March 31 and the first fall frost is November 7, giving you a growing season of approximately 221 days.
At an elevation of 3,170 feet, King County receives approximately 60.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 99°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.
King County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.8-8.4
Drainage
Well Drained
Plant 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 King County
How your county's soil matches Marigolds's growing requirements.
Soil pH
Your soil pH (7.8–8.4) is more alkaline than Marigolds prefers (6.0–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in King 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 low (1.1%). Add 2-3 inches of compost before planting Marigolds.
How to Plant Marigolds
Succession Planting Marigolds
Sow every 5.7 weeks. Last sowing by Aug 29 to harvest before frost.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 4.7" | 0" | ❄️ Dormant |
| Feb | — | 3.2" | 0" | ❄️ Dormant |
| Mar | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 1.5" | 0.7" | 💧 Light watering |
| Jun | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 10.4" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 11.5" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 8.1" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 5.7" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 3" | 0" | ✅ Rainfall sufficient |
| Dec | — | 3.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in King 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 — King County, TX
Marigolds Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | May 12 | May 12 – May 26 |
| Transplant Outdoors | March 24 | Mar 24 – Apr 7 |
| Direct Sow | March 24 | Mar 24 – Apr 14 |
| Harvest | May 19 | May 19 – Sep 22 |
Plant 0.3" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Start Indoors Harvest |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| 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 8a
📆 Growing Season
221 days in King County
Growing Tips for Marigolds in King County
Direct sow Marigolds outdoors after March 31 in King County when soil has warmed and frost danger has passed.
Sandy soil in King 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 99°F in King 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 60" of annual rainfall in King 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 King County, TX?
King County is in Zone 8a with an average last frost of March 31. Plan your Marigolds planting based on this frost date — see the calendar above for exact timing.
What planting zone is King County, TX?
King County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 31 and first fall frost is November 7.
Your King County Garden Planner — Free
A 24-page printable planner built for King County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.