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When to plant Garlic in Henry County County,

Aim to plant Garlic in Henry County County on or after mid-spring; the window stays open through late spring. Henry County County's 183-day frost-free season gives you enough for a full main crop and a short fall succession. A second sowing from September 4 to September 18 extends the harvest into fall.

When to Plant Garlic in Henry County, IL

Garlic
Henry County, Illinois Zone 5b June

What to do in June

June is a pivotal month for Henry County, Illinois gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 16
Avg. first frost October 16
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 15 hrs

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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.

Henry County, Illinois is in USDA Zone 5b. The average last spring frost is April 16 and the first fall frost is October 16, giving you a growing season of approximately 183 days.

At an elevation of 593 feet, Henry County receives approximately 31.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Garlic during the growing season.

Henry County, IL (Zone 5b) Moderate season
183 days
Last Spring Frost April 16
183 growing days
First Fall Frost October 16
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Henry County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-7.2

Drainage

Well Drained

Garlic Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Transplant: Apr 10 🍅 Harvest: Jul 10 – Sep 25
Recommended (50%) ✓ Fits season (15 days to spare)
Transplant: Apr 16 🍅 Harvest: Jul 16 – Oct 1
Safe Start (90%) ✓ Fits season (17 days to spare)
Transplant: May 2 🍅 Harvest: Aug 1 – Oct 17

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 Henry County

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

Soil pH

Your soil pH (6.3–7.2) is within Garlic's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Garlic will thrive.

How to Plant Garlic

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 6 weeks before your first frost date for a fall harvest.

Garlic Water Budget

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

Monthly Watering Guide for Garlic

Garlic 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 Garlic Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.2" 3" 0" ✅ Rainfall sufficient
May 2.2" 3.5" 0" ✅ Rainfall sufficient
Jun 2.2" 4.6" 0" ✅ Rainfall sufficient
Jul 2.2" 3.3" 0" ✅ Rainfall sufficient
Aug 2.2" 3.4" 0" ✅ Rainfall sufficient
Sep 2.2" 3" 0" ✅ Rainfall sufficient
Oct 2.2" 2.4" 0" ✅ Rainfall sufficient
Nov 1.9" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Garlic 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.

Garlic needs ~2,516 GDD — county provides 2,790 GDD Good fit

Garlic Planting Timeline — Henry County, IL

Garlic Planting Calendar

Activity When Date Range
Harvest December 4 Dec 4 – Feb 19
Fall Sowing September 4 Sep 4 – Sep 18

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

90–240 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

183 days in Henry County

Growing Tips for Garlic in Henry County

Direct sow Garlic outdoors after April 16 in Henry County when soil has warmed and frost danger has passed.

Your 183.0-day growing season in Henry County is tight for Garlic (90.0-240.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Garlic in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

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 Henry County, IL?

Henry County is in Zone 5b with an average last frost of April 16. Plan your Garlic planting based on this frost date — see the calendar above for exact timing.

What planting zone is Henry County, IL?

Henry County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 16 and first fall frost is October 16.

When should I plant Garlic in Henry County, ?

In Henry County, , plant Garlic after the last frost (around April 16) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Henry County, for Garlic?

Henry County sits in USDA Zone 5b. Garlic grows reliably in zones 3a through 9b, so it's a good fit here.

Can Garlic grow in Henry County's climate?

Yes — Garlic grows well in Henry County's temperate climate. Henry County averages a 183-day frost-free season, with last frost around April 16 and first frost around October 16.

🌱

Your Henry County Garden Planner — Free

A 22-page printable planner built for Henry County (Zone 5b). 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 Henry County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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