When to Plant Eggplant in Peterborough, ON
Eggplant is a heat-loving solanaceous crop that produces glossy fruits in purple, white, or striped varieties. It requires long, warm growing seasons for best production.
Peterborough, Ontario is in USDA Zone 6b. The average last spring frost is April 13 and the first fall frost is October 17, giving you a growing season of approximately 187 days.
At an elevation of 656 feet, Peterborough receives approximately 40.6 inches of rainfall annually with predominantly clay loam soil. Summer highs average 81°F, so choose short-season varieties of Eggplant to ensure they mature before fall. Clay soil retains moisture well for Eggplant, but amend with compost to improve drainage and prevent root rot.
Peterborough Soil Profile
Soil Type
Clay Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Plant Planting Risk Windows
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.
How to Plant Eggplant
How Much Eggplant to Grow
For a family of 4, plant approximately 8 eggplant plants in about 70 sq ft. In Peterborough's 187-day season, you'll have plenty of time for a full harvest. Plan your garden layout →
Plant Water Budget
Monthly Watering Guide for Eggplant
Eggplant needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.
| Month | Eggplant Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.9" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.8" | 0" | ❄️ Dormant |
| Apr | 4.8" | 4.3" | 0.5" | 💧 Light watering |
| May | 4.8" | 4.5" | 0.3" | 💧 Light watering |
| Jun | 4.8" | 5.1" | 0" | ✅ Rainfall sufficient |
| Jul | 4.8" | 5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.8" | 3.8" | 1" | 💧 Light watering |
| Sep | 4.8" | 3.8" | 1" | 💧 Light watering |
| Oct | 4.8" | 3.1" | 1.7" | 💧 Light watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 2.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Peterborough). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Eggplant 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.
Eggplant Planting Timeline — Peterborough, ON
Eggplant Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 2 | Feb 2 – Feb 16 |
| Transplant Outdoors | April 27 | Apr 27 – May 11 |
| Direct Sow | April 20 | Apr 20 – May 11 |
| Harvest | July 6 | Jul 6 – Sep 7 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · Only during dry spells
📅 Days to Maturity
65–85 days
🧪 Soil pH
Needs 5.5–7 · Your soil: N/A
🗺️ USDA Zone
Zone 6b
📆 Growing Season
187 days in Peterborough
Growing Tips for Eggplant in Peterborough
Common pests for Eggplant in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 8-10 weeks before last frost. Transplant only after nighttime temperatures stay above 55F. Mulch to retain moisture and warmth around roots.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Eggplant in Other Locations
Frequently Asked Questions
When should I plant Eggplant in Peterborough, ON?
Peterborough is in Zone 6b with an average last frost of April 13. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.
What planting zone is Peterborough, ON?
Peterborough, Ontario is in USDA Hardiness Zone 6b. The average last spring frost is April 13 and first fall frost is October 17.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Peterborough gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.
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