When to plant Marigolds in Weld County County,
Plant Marigolds in Weld County County after May 2; the prime window is May 9–May 30.
When to Plant Marigolds in Weld County, CO
June in the garden — Weld County, Colorado
Your Weld County, Colorado garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
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Sow marigolds in trays indoors
Your window is short. These crops want several weeks of indoor growth before they go outside.
Before July 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.
Weld County, Colorado is in USDA Zone 5b. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.
At an elevation of 6,992 feet, Weld County receives approximately 18.8 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Marigolds during the growing season. With low rainfall, drip irrigation is essential for growing Marigolds successfully. Mulch heavily to conserve soil moisture.
Weld County Soil Profile
Soil Type
Loam
Soil pH
6.6-8.1
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 Weld County
How your county's soil matches Marigolds's growing requirements.
Soil pH
Your soil pH (6.6–8.1) overlaps with Marigolds's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Weld County is excellent for Marigolds — good drainage, moisture retention, and nutrient holding capacity.
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 Jul 29 to harvest before frost.
Marigolds Water Budget
Water stress score is 8/10 — 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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | — | 2.1" | 0" | ❄️ Dormant |
| May | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| Jul | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Aug | 2.2" | 1.8" | 0.4" | 💧 Light watering |
| Sep | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Oct | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Nov | — | 1.2" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Weld 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 — Weld County, CO
Marigolds Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 21 | Mar 21 – Apr 4 |
| Transplant Outdoors | May 9 | May 9 – May 23 |
| Direct Sow | May 9 | May 9 – May 30 |
| Bloom | July 4 | Jul 4 – Oct 3 |
Plant 0.3" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Only during dry spells
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
158 days in Weld County
Growing Tips for Marigolds in Weld County
Direct sow Marigolds outdoors after May 02 in Weld County when soil has warmed and frost danger has passed.
Common pests for Marigolds in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
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 Weld County, CO?
Weld County is in Zone 5b with an average last frost of May 2. Plan your Marigolds planting based on this frost date — see the calendar above for exact timing.
What planting zone is Weld County, CO?
Weld County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 2 and first fall frost is October 7.
When should I plant Marigolds in Weld County, ?
In Weld County, , plant Marigolds after the last frost (around May 2) and before the first frost (around October 7). Best results when soil holds above 50°F.
What growing zone is Weld County, for Marigolds?
Weld County sits in USDA Zone 5b. Marigolds grows reliably in zones 2a through 11b, so it's a good fit here.
Can Marigolds grow in Weld County's climate?
Yes — Marigolds grows well in Weld County's temperate climate. Weld County averages a 158-day frost-free season, with last frost around May 2 and first frost around October 7.
Your Weld County Garden Planner — Free
A 22-page printable planner built for Weld County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.