When to plant Marigolds in Guthrie County County,
Guthrie County County gardeners should plant Marigolds between May 3 and May 24 in spring. With Guthrie County County's Zone 5a climate (last frost April 26), Marigolds needs 70 days to mature — plant by July 28 for a full harvest.
When to Plant Marigolds in Guthrie County, IA
What to do in June
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Guthrie County, Iowa.
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Begin indoor sowing: marigolds
Starting these indoors now means sturdy transplants ready the moment your soil warms up.
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Harvest marigolds as they ripen
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
July 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.
Guthrie County, Iowa is in USDA Zone 5a. The average last spring frost is April 26 and the first fall frost is October 6, giving you a growing season of approximately 163 days.
At an elevation of 1,378 feet, Guthrie County receives approximately 31.7 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.
Guthrie County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-6.7
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 Guthrie County
How your county's soil matches Marigolds's growing requirements.
Soil pH
Your soil pH (5.9–6.7) overlaps with Marigolds's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Guthrie County is excellent for Marigolds — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.1%) — Marigolds will thrive.
How to Plant Marigolds
Succession Planting Marigolds
Sow every 5.7 weeks. Last sowing by Jul 28 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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.1" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.4" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2" | 0" | ❄️ Dormant |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Guthrie 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 — Guthrie County, IA
Marigolds Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 15 | Mar 15 – Mar 29 |
| Transplant Outdoors | May 3 | May 3 – May 17 |
| Direct Sow | May 3 | May 3 – May 24 |
| Bloom | June 28 | Jun 28 – Sep 20 |
Plant 0.3" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| 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: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
163 days in Guthrie County
Growing Tips for Marigolds in Guthrie County
Direct sow Marigolds outdoors after April 26 in Guthrie 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 Guthrie County, IA?
Guthrie County is in Zone 5a with an average last frost of April 26. Plan your Marigolds planting based on this frost date — see the calendar above for exact timing.
What planting zone is Guthrie County, IA?
Guthrie County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 26 and first fall frost is October 6.
When should I plant Marigolds in Guthrie County County, ?
In Guthrie County County, , plant Marigolds after the last frost (around April 26) and before the first frost (around October 6). Best results when soil holds above 50°F.
What growing zone is Guthrie County County, for Marigolds?
Guthrie County 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 Guthrie County County's climate?
Yes — Marigolds grows well in Guthrie County County's temperate climate. Guthrie County County averages a 163-day frost-free season, with last frost around April 26 and first frost around October 6.
Your Guthrie County Garden Planner — Free
A 22-page printable planner built for Guthrie 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.