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When to plant Marigolds in Madison County, IL

Spring Marigolds in Madison County goes in April 11–May 2, once nighttime temps stop dipping near freezing.

When to Plant Marigolds in Madison County, IL

Madison County, Illinois Zone 7a August

Your August game plan for Madison County, Illinois

Each item below is timed to Madison County, Illinois's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 11
Avg. first frost October 22
Soil temp (4") 84°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Start harvesting marigolds

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

September prep starts now
  • First harvests: marigolds

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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.

Madison County, Illinois is in USDA Zone 7a. The average last spring frost is April 11 and the first fall frost is October 22, giving you a growing season of approximately 194 days.

At an elevation of 963 feet, Madison County receives approximately 36.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Marigolds during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Madison County, IL (Zone 7a) Moderate season
194 days
Last Spring Frost April 11
194 growing days
First Fall Frost October 22

Madison County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Marigolds Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Start indoors: Feb 21 Transplant: Apr 4 🌸 Bloom: May 30 – Sep 5
Recommended (50%) ✓ Fits season (40 days to spare)
Start indoors: Feb 28 Transplant: Apr 11 🌸 Bloom: Jun 6 – Sep 12
Safe Start (90%) ✓ Fits season (45 days to spare)
Start indoors: Mar 9 Transplant: Apr 20 🌸 Bloom: Jun 15 – Sep 21

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 Madison County

How your county's soil matches Marigolds's growing requirements.

Soil pH

Your soil pH (5.8–6.9) overlaps with Marigolds's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Madison County is excellent for Marigolds — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.8%) — Marigolds will thrive.

How to Plant Marigolds

0.3"
Planting Depth
10"
Between Plants
12"
Between Rows

Succession Planting Marigolds

4
successive plantings in your 194-day season

Sow every 5.7 weeks. Last sowing by Aug 13 to harvest before frost.

Marigolds Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.2" 4" 0" ✅ Rainfall sufficient
May 2.2" 3.6" 0" ✅ Rainfall sufficient
Jun 2.2" 5" 0" ✅ Rainfall sufficient
Jul 2.2" 4.1" 0" ✅ Rainfall sufficient
Aug 2.2" 4.1" 0" ✅ Rainfall sufficient
Sep 2.2" 3.4" 0" ✅ Rainfall sufficient
Oct 2.2" 2.8" 0" ✅ Rainfall sufficient
Nov 2.8" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Madison 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 needs ~1,005 GDD — county provides 3,249 GDD Excellent fit

Marigolds Planting Timeline — Madison County, IL

Marigolds Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors April 11 Apr 11 – Apr 25
Direct Sow April 11 Apr 11 – May 2
Bloom June 6 Jun 6 – Sep 12

Plant 0.3" deep · 10" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May 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 7a

📆 Growing Season

194 days in Madison County

Growing Tips for Marigolds in Madison County

Direct sow Marigolds outdoors after April 11 in Madison 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

  • Beans
  • Cabbage

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Marigolds Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower heads dry on plant. Pull dried petals to reveal seeds.
Storage Store in envelopes; viable 3 years at 35°F, under 50% humidity.

Very easy to save. Seeds are the long, thin, dark pieces inside the dried flower head.

Frequently Asked Questions

When should I plant Marigolds in Madison County, IL?

Madison County is in Zone 7a with an average last frost of April 11. Plan your Marigolds planting based on this frost date — see the calendar above for exact timing.

What planting zone is Madison County, IL?

Madison County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 11 and first fall frost is October 22.

When should I plant Marigolds in Madison County, IL?

In Madison County, IL, plant Marigolds after the last frost (around April 11) and before the first frost (around October 22). Best results when soil holds above 50°F.

What growing zone is Madison County, IL for Marigolds?

Madison County sits in USDA Zone 7a. Marigolds grows reliably in zones 2a through 11b, so it's a good fit here.

Can Marigolds grow in Madison County's climate?

Yes — Marigolds grows well in Madison County's temperate climate. Madison County averages a 194-day frost-free season, with last frost around April 11 and first frost around October 22.

🌱

Your Madison County Garden Planner — Free

A 22-page printable planner built for Madison County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Madison County, IL. Local conditions may vary. Last updated: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.