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When to plant Garlic in Forsyth, IL

Forsyth sits in USDA Zone 6a. Plant Garlic between mid-spring (after last frost on April 13) and late spring. A second sowing from September 7 to September 21 extends the harvest into fall.

When to Plant Garlic in Forsyth, IL

Garlic
Macon County, Illinois Zone 6a June

June to-do list for Macon County, Illinois

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

Avg. last frost April 13
Avg. first frost October 19
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 14.8 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.

Forsyth, Illinois is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 19, giving you a growing season of approximately 189 days.

At an elevation of 1,064 feet, Macon County receives approximately 31.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Garlic during the growing season.

Forsyth, IL (Zone 6a) Moderate season
189 days
Last Spring Frost April 13
189 growing days
First Fall Frost October 19

Forsyth Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.1

Drainage

Well Drained

Garlic Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 7 🍅 Harvest: Jul 7 – Oct 20
Recommended (50%) ✗ May not fit
Transplant: Apr 13 🍅 Harvest: Jul 13 – Oct 26
Safe Start (90%) ✗ May not fit
Transplant: Apr 24 🍅 Harvest: Jul 24 – Nov 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 Forsyth

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

Soil pH

Your soil pH (6.0–7.1) is within Garlic's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Macon 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 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.2" 2.9" 0" ✅ Rainfall sufficient
May 2.2" 3.1" 0" ✅ Rainfall sufficient
Jun 2.2" 4.1" 0" ✅ Rainfall sufficient
Jul 2.2" 3.5" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2.9" 0" ✅ Rainfall sufficient
Oct 2.2" 2.3" 0" ✅ Rainfall sufficient
Nov 2.4" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Macon 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 ~2,392 GDD — county provides 2,740 GDD Good fit

Garlic Planting Timeline — Forsyth, IL

Garlic Planting Calendar

Activity When Date Range
Harvest December 7 Dec 7 – Mar 22
Fall Sowing September 7 Sep 7 – Sep 21

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

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

90–240 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

189 days in Macon County

Growing Tips for Garlic in Forsyth

Direct sow Garlic outdoors after April 13 in Macon County when soil has warmed and frost danger has passed.

Your 189.0-day growing season in Macon 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 →

When should I plant Garlic in Forsyth, IL?

In Forsyth, IL, plant Garlic after the last frost (around April 13) and before the first frost (around October 19). Best results when soil holds above 50°F.

What growing zone is Forsyth, IL for Garlic?

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

Can Garlic grow in Forsyth's climate?

Yes — Garlic grows well in Forsyth's temperate climate. Forsyth averages a 189-day frost-free season, with last frost around April 13 and first frost around October 19.

🌱

Your Macon County Garden Planner — Free

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