When to Plant Broccoli in Hamilton, ON
Broccoli is a nutrient-dense cool-season crop that produces large central heads followed by smaller side shoots. It is one of the most popular garden vegetables.
Hamilton, Ontario is in USDA Zone 8a. The average last spring frost is March 26 and the first fall frost is November 1, giving you a growing season of approximately 220 days.
At an elevation of 246 feet, Hamilton receives approximately 45.6 inches of rainfall annually with predominantly clay loam soil. Summer highs average 93°F, providing good warmth for Broccoli during the growing season. Clay soil retains moisture well for Broccoli, but amend with compost to improve drainage and prevent root rot.
Hamilton Soil Profile
Soil Type
Clay Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Broccoli 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 Broccoli
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
How Much Broccoli to Grow
For a family of 4, plant approximately 12 broccoli plants in about 30 sq ft. In Hamilton's 220-day season, you'll have plenty of time for a full harvest. Plan your garden layout →
Broccoli Water Budget
Monthly Watering Guide for Broccoli
Broccoli needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Broccoli Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2" | 0" | ❄️ Dormant |
| Feb | — | 2.2" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.3" | 1" | 💧 Light watering |
| Apr | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| May | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 6.4" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 5.3" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Sep | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Oct | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Nov | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Dec | — | 2.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Hamilton). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Broccoli 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.
Broccoli Planting Timeline — Hamilton, ON
Broccoli Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 19 | Feb 19 – Mar 5 |
| Transplant Outdoors | March 26 | Mar 26 – Apr 9 |
| Direct Sow | March 12 | Mar 12 – Apr 2 |
| Harvest | May 28 | May 28 – Jul 9 |
| Fall Sowing | August 23 | Aug 23 – Sep 6 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 8a
📆 Growing Season
220 days in Hamilton
Growing Tips for Broccoli in Hamilton
Summer highs in Hamilton reach 93°F — grow Broccoli as a spring or fall crop. Use shade cloth if planting in summer.
Common pests for Broccoli in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 6-8 weeks before last frost. Provide consistent moisture to prevent hollow stems. Harvest heads before yellow flowers appear.
Recommended Broccoli Varieties for Hamilton
Heat-tolerant broccoli — plant as early spring or fall crop
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Isolate 1/2 mile from other brassicas. Biennial — must overwinter roots.
Broccoli in Other Locations
Frequently Asked Questions
When should I plant Broccoli in Hamilton, ON?
Hamilton is in Zone 8a with an average last frost of March 26. Plan your Broccoli planting based on this frost date — see the calendar above for exact timing.
What planting zone is Hamilton, ON?
Hamilton, Ontario is in USDA Hardiness Zone 8a. The average last spring frost is March 26 and first fall frost is November 1.
Your Hamilton Garden Planner — Free
A 22-page printable planner built for Hamilton (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.