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When to plant Crocus in Madison County County,

In Zone 7a (Madison County County), direct-sow Crocus between mid-spring and late spring for spring, after the April 11 last-frost mark. A second sowing from September 17 to October 1 extends the harvest into fall.

When to Plant Crocus in Madison County, IL

Madison County, Illinois Zone 7a June

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Avg. last frost April 11
Avg. first frost October 22
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 14.7 hrs

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Crocuses (Crocus spp.) are the heralds of spring — small, gem-like blooms that push up through frozen ground or even snow, often weeks before any other flower. Their compact corms naturalize readily in lawns, rock gardens, and borders, creating drifts of purple, white, and yellow that expand year after year. Bees prize early crocus as one of their first nectar and pollen sources of the season. The saffron crocus (C. sativus) blooms in fall and yields the world's most expensive spice.

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 Crocus during the growing season.

Bulb Blooms in Spring Pollinator-friendly Fragrant
Madison County, IL (Zone 7a) Moderate season
194 days
Last Spring Frost April 11
194 growing days
First Fall Frost October 22
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Madison County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Crocus Planting Risk Windows

Early Start (70% safe) ✓ Fits season (210 days to spare)
Transplant: Apr 4 🌸 Bloom: Feb 28 – Mar 21
Recommended (50%) ✓ Fits season (208 days to spare)
Transplant: Apr 11 🌸 Bloom: Mar 7 – Mar 28
Safe Start (90%) ✓ Fits season (213 days to spare)
Transplant: Apr 20 🌸 Bloom: Mar 16 – Apr 6

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 Crocus's growing requirements.

Soil pH

Your soil pH (5.8–6.9) overlaps with Crocus's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Crocus

4"
Planting Depth
3"
Between Plants
4"
Between Rows

Fall planting: Sow 5 weeks before your first frost date for a fall harvest.

Succession Planting Crocus

24
successive plantings in your 194-day season

Sow every 1.1 weeks. Last sowing by Oct 02 to harvest before frost.

For a dedicated fall crop, sow by Sep 17.

Crocus 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 Crocus

Crocus 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 Crocus 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.

Crocus 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.

Crocus needs ~251 GDD — county provides 3,249 GDD Excellent fit

Crocus Planting Timeline — Madison County, IL

Crocus Planting Calendar

Activity When Date Range
Bloom August 13 Aug 13 – Sep 3
Fall Sowing September 17 Sep 17 – Oct 1

Plant 4" deep · 3" apart · Rows 4" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June
July
August Bloom
September Fall Sowing Bloom
October Fall Sowing
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

10–20 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

194 days in Madison County

Growing Tips for Crocus in Madison County

Direct sow Crocus outdoors after April 11 in Madison County when soil has warmed and frost danger has passed.

Your generous 194.0-day season in Madison County allows multiple plantings of Crocus. Sow every 5.0 days for continuous harvest.

General growing tips

Plant corms 3–4 inches deep and 2–3 inches apart in fall, when soil temperature drops below 60°F. Mass plantings (at least 25 corms per cluster) create the most visual impact. Plant in well-drained soil — corms rot in standing water. Crocus naturalize well under deciduous trees; the tree leafs out after crocus dormancy begins, so light competition is minimal. Squirrels and chipmunks dig corms — plant deeper (4 inches) or use wire mesh baskets in high-predation areas. Allow foliage to die back naturally before mowing lawns. In zones 8a–8b, plant in December with pre-chilled corms for best results.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Crocus in Madison County, IL?

Madison County is in Zone 7a with an average last frost of April 11. Plan your Crocus 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 Crocus in Madison County County, ?

In Madison County County, , plant Crocus 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 County, for Crocus?

Madison County County sits in USDA Zone 7a. Crocus grows reliably in zones 3a through 8b, so it's a good fit here.

Can Crocus grow in Madison County County's climate?

Yes — Crocus grows well in Madison County County's temperate climate. Madison County 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: June 2026.

Sources & credits

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