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When to plant Garlic in Hamilton County, IL

The best window to plant Garlic in Hamilton County, is mid-spring–late spring, when soil warms to 50°F. Last frost typically hits April 9; first frost October 23. A second sowing from September 11 to September 25 extends the harvest into fall.

When to Plant Garlic in Hamilton County, IL

Garlic

Garlic is a pungent allium planted in fall and harvested the following summer. Hardneck varieties produce edible flower stalks (scapes) and are more cold-hardy.

Hamilton County, Illinois is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 23, giving you a growing season of approximately 197 days.

At an elevation of 524 feet, Hamilton County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Garlic during the growing season.

Hamilton County, IL (Zone 6b) Moderate season
197 days
Last Spring Frost April 9
197 growing days
First Fall Frost October 23

Hamilton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Monthly Watering Guide for Garlic

Garlic needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Garlic Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Hamilton County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Garlic Planting Timeline — Hamilton County, IL

Garlic Planting Calendar

Activity When Date Range
Harvest December 11 Dec 11 – Mar 26
Fall Sowing September 11 Sep 11 – Sep 25

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January Harvest
February Harvest
March Harvest
April
May
June
July
August
September Fall Sowing
October
November
December Harvest

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

90–240 days

🧪 Soil pH

Needs 6–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 6b

📆 Growing Season

197 days in Hamilton County

Growing Tips for Hamilton County

Plant individual cloves pointed end up in fall, 6 weeks before ground freezes. Mulch heavily with straw. Harvest when lower leaves begin to brown but 5-6 green leaves remain.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Garlic in Hamilton County, IL?

Hamilton County is in Zone 6b with an average last frost of April 9. Plan your Garlic planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hamilton County, IL?

Hamilton County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 23.

When should I plant Garlic in Hamilton County, IL?

In Hamilton County, IL, plant Garlic after the last frost (around April 9) and before the first frost (around October 23). Best results when soil holds above 50°F.

What growing zone is Hamilton County, IL for Garlic?

Hamilton County sits in USDA Zone 6b. Garlic grows reliably in zones 3a through 9b, so it's a good fit here.

Can Garlic grow in Hamilton County's climate?

Yes — Garlic grows well in Hamilton County's temperate climate. Hamilton County averages a 197-day frost-free season, with last frost around April 9 and first frost around October 23.

🌱

Your Hamilton County Garden Planner — Free

A 22-page printable planner built for Hamilton County (Zone 6b). 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 Hamilton County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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