When to Plant Garlic in Thunder Bay, ON
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.
Thunder Bay, Ontario is in USDA Zone 4b. The average last spring frost is May 7 and the first fall frost is October 1, giving you a growing season of approximately 147 days.
At an elevation of 652 feet, Thunder Bay receives approximately 20.5 inches of rainfall annually with predominantly clay loam soil. Summer highs average 72°F, so choose short-season varieties of Garlic to ensure they mature before fall. Clay soil retains moisture well for Garlic, but amend with compost to improve drainage and prevent root rot.
Thunder Bay Soil Profile
Soil Type
Clay Loam
Soil pH
6.0-7.0
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 | — | 0.9" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.2" | 0" | ❄️ Dormant |
| Apr | — | 1.8" | 0" | ❄️ Dormant |
| May | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Jun | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Jul | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Aug | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Sep | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Oct | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Nov | — | 1.3" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Thunder Bay). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Garlic Planting Timeline — Thunder Bay, ON
Garlic Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Harvest | November 19 | Nov 19 – Jan 14 |
| Fall Sowing | August 20 | Aug 20 – Sep 3 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Harvest |
| February | — |
| March | — |
| April | — |
| May | — |
| June | — |
| July | — |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | Harvest |
| 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 4b
📆 Growing Season
147 days in Thunder Bay
Growing Tips for Thunder Bay
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
Check more plant combinations with our Companion Planting Checker →
Garlic in Other Locations
Frequently Asked Questions
When should I plant Garlic in Thunder Bay, ON?
Thunder Bay is in Zone 4b with an average last frost of May 7. Plan your Garlic planting based on this frost date — see the calendar above for exact timing.
What planting zone is Thunder Bay, ON?
Thunder Bay, Ontario is in USDA Hardiness Zone 4b. The average last spring frost is May 7 and first fall frost is October 1.
Your Thunder Bay Garden Planner — Free
A 22-page printable planner built for Thunder Bay (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.