When to plant Marigolds in Marshall County, IA
The best window to plant Marigolds in Marshall County, is May 9–May 30, when soil warms to 50°F. Last frost typically hits May 2; first frost October 7.
When to Plant Marigolds in Marshall County, IA
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.
Marshall County, Iowa is in USDA Zone 5a. 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 1,379 feet, Marshall County receives approximately 33.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Marigolds to ensure they mature before fall.
Marshall County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Marigolds Planting Timeline — Marshall County, IA
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 – Sep 26 |
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 | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 6–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 5a
📆 Growing Season
158 days in Marshall County
Growing Tips for Marshall County
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 Marshall County, IA?
Marshall County is in Zone 5a 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 Marshall County, IA?
Marshall County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 2 and first fall frost is October 7.
When should I plant Marigolds in Marshall County, IA?
In Marshall County, IA, 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 Marshall County, IA for Marigolds?
Marshall County sits in USDA Zone 5a. Marigolds grows reliably in zones 2a through 11b, so it's a good fit here.
Can Marigolds grow in Marshall County's climate?
Yes — Marigolds grows well in Marshall County's temperate climate. Marshall County averages a 158-day frost-free season, with last frost around May 2 and first frost around October 7.
Your Marshall County Garden Planner — Free
A 22-page printable planner built for Marshall County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.