Last Frost Date Windsor Ontario — When Is It Safe to Plant?
Windsor's last frost is April 20 — first frost October 28, ~190-day season, Zone 7a. Canada's warmest inland city — where sweet potatoes, okra, and melons are routine crops.
Windsor's last frost date is April 20. First fall frost doesn't arrive until around October 28, giving Windsor approximately 190 frost-free days. Zone 7a makes Windsor the warmest major inland city in Canada — a designation that means more than just mild winters. It means crops that are impossible or risky everywhere else in Ontario are routine here.
Sweet potatoes, okra, peanuts, melons, and long-season heirloom tomatoes are all reliable in Windsor. If you've been told something "won't grow in Canada" — check whether it'll grow in Windsor first. Use this guide alongside the seed starting calculator to build your full planting schedule.
For a deeper dive on Windsor's frost dates — the neighbourhood breakdown (Detroit River core, LaSalle and Tecumseh, the Lake Erie shore at Leamington and Kingsville, Pelee Island), why Windsor is Canada's warmest inland city, comparison to Toronto and Hamilton, and frost protection — see the dedicated Last Frost Date Windsor page.
Windsor at a glance: Last frost April 20 · First frost October 28 · Growing season ~190 days · Hardiness zone 7a · Canada's warmest inland city. Safe to transplant tomatoes, peppers, and cucumbers outdoors after May 1–5.
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A printable one-page PDF — seed-starting, transplant, direct-sow and harvest dates for 30+ crops, from your local frost dates.
📅 Windsor's Key Frost Dates
Windsor Planting Calendar — Full Table
All dates calculated from Windsor's average last frost of April 20.
| Vegetable | Start Indoors | Transplant / Direct Sow | Fall Sow | Notes |
|---|---|---|---|---|
| 🍅 Tomatoes | Mar 1–15 | May 1–10 | — | Any variety — 90-day heirlooms reliable |
| 🌶️ Peppers | Feb 15–Mar 1 | May 5–15 | — | Hot peppers fully reliable in Zone 7a |
| 🍠 Sweet Potatoes | Mar 15–Apr 1 (slips) | May 10–20 | — | Routine crop in Windsor — not an experiment |
| 🌿 Okra | Mar 15–Apr 1 | May 10–20 | — | One of the only Canadian cities where this works |
| 🥒 Cucumbers | Apr 1–10 | May 1–10 | — | Direct sow after May 5 also reliable |
| 🍉 Watermelon / Melon | Apr 1–10 | May 10–20 | — | Full-size melons feasible — use black mulch |
| 🎃 Squash / Pumpkin | Apr 1–10 | May 1–10 | — | Giant pumpkins feasible with long season |
| 🌽 Sweet Corn | — | May 1–Jun 15 direct | — | 3–4 successions possible |
| 🫘 Beans | — | May 1–Jul 1 direct | — | Succession sow; dry beans also feasible |
| 🥦 Broccoli / Brassicas | Mar 1–15 | Apr 15–May 5 | Jun 15–Jul 1 | Two crops per year |
| 🥬 Lettuce | Feb 15–Mar 15 | Apr 1–May 10 | Aug 1–Sept 15 | Bolts in July heat — shade helps |
| 🌿 Spinach / Peas | — | Mar 15–Apr 20 direct | Aug 15–Sept 15 | Spring and fall; avoid July heat |
| 🥕 Carrots | — | Apr 1–Jun 15 direct | — | Multiple successions |
| 🧄 Garlic | — | Oct 15–30 (fall) | — | Softneck varieties also possible in Zone 7a |
| 🧅 Onions | Jan 20–Feb 5 | Apr 15–May 1 | — | Earliest indoor start in Ontario |
| 🥜 Peanuts | Apr 1–15 | May 15–25 | — | Only reliable in Windsor in all of Canada |
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What Windsor's Zone 7a Makes Possible
Sweet Potatoes
Not an experiment in Windsor — a reliable crop. The 190-day season gives sweet potatoes the 100+ warm days they need. Beauregard and Georgia Jet are the go-to varieties. Use black plastic mulch to warm soil faster in spring.
Okra
Windsor is one of the only places in Canada where okra grows reliably. It needs consistent heat above 25°C — exactly what Zone 7a provides in July and August. Clemson Spineless (55 days) is the most reliable variety. Start indoors mid-March.
Full-Size Melons
While Toronto and Hamilton gardeners stick to compact watermelons, Windsor can grow full-size cantaloupe, honeydew, and large watermelons (80–90 days). Use black plastic mulch and the warmest spot in your garden.
Peanuts
Windsor is essentially the only place in Canada where peanuts are a viable garden crop. They need 120+ frost-free days of warm soil — a stretch anywhere else in the country. Start indoors early April, transplant mid-May. A genuine novelty with real yield.
Any Tomato Variety
Windsor's season length and summer heat means you're not limited to 65-day varieties like Prairie gardeners. Brandywine (80 days), Cherokee Purple (80 days), Mortgage Lifter (85 days) — all ripen comfortably before frost. The best tomato city in Ontario.
Hot Peppers
Zone 7a summers give hot peppers the sustained heat they need to ripen fully and develop full heat. Jalapeños, habaneros, and cayennes all perform well. Start indoors in mid-February, transplant mid-May into the warmest spot available.
How Windsor Compares to Other Canadian Cities
| Windsor | Toronto | Hamilton | Vancouver | |
|---|---|---|---|---|
| Zone | 7a ✓ | 6b | 6b/7a | 8b |
| Last frost | Apr 20 | Apr 20 | Apr 25 | Mar 15 |
| First frost | Oct 28 | Nov 1 | Oct 28 | Nov 30 |
| Season | ~190 days | ~197 days | ~186 days | ~260 days |
| Unique crops | Okra, peanuts, sweet potatoes ✓ | Sweet potatoes, heirlooms | Sweet potatoes, melons | Year-round greens |
Frequently Asked Questions
What is the last frost date in Windsor Ontario ?
Windsor's last frost date is April 20 (Zone 7a). For frost-sensitive crops like tomatoes and peppers, add a 1–2 week buffer and transplant outdoors around May 1–5. Windsor's long warm season and Zone 7a designation make it the most productive gardening climate of any major inland Canadian city.
What growing zone is Windsor Ontario?
Windsor is Zone 7a — the warmest hardiness zone of any major inland Canadian city. This means mild winters, hot summers, and a ~190-day growing season that supports crops simply not feasible anywhere else in Ontario.
Can I grow okra in Windsor Ontario?
Yes — Windsor is one of the only Canadian cities where okra grows reliably. Start indoors mid-March, transplant after May 10 when soil is warm. Clemson Spineless (55 days) is the most reliable variety. Not feasible in Toronto, Hamilton, or any city further north or west.
Can I grow sweet potatoes in Windsor Ontario?
Absolutely — sweet potatoes are a routine crop in Windsor, not an experiment. Start slips indoors in early April, transplant mid-May, harvest before first frost in late October. Beauregard (90 days) is the most reliable variety. Use black plastic mulch to warm the soil faster.
When should I start tomatoes indoors in Windsor?
Start tomato seeds indoors between March 1 and March 15. Windsor's long season allows any tomato variety including 85–90 day heirlooms. Transplant outdoors around May 1–10 after hardening off. With first frost not until late October, you have 190 days to work with.
📖 Related Guides & Calculators
Plan your Windsor garden from seed to harvest.
Plan Your Windsor Garden
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