What to Plant in May Canada
On this page
What to plant in May in Canada depends entirely on your zone — this page answers it for every band. May is the biggest month in the Canadian garden. Transplant tomatoes, peppers and squash after your last frost — mid-May in southern Ontario, late May on the Prairies — and direct sow beans and corn once soil reaches 10-15°C.
May planting by region
| Band | Sow outdoors | Start indoors | Plant out | Harvest now |
|---|---|---|---|---|
|
Long season Zones 7-9 |
Beans, corn, cucurbits; succession lettuce and radish. | Fall brassicas late month. | Tomatoes, peppers, eggplant after the last frost. | Asparagus, radish, lettuce, spinach, rhubarb, early peas. |
|
Medium season Zones 4-6 |
Beans and corn after mid-month; carrots, beets, chard. | Fall brassicas late month. | Tomatoes, peppers and squash after the last frost (mid-to-late May). | Asparagus, rhubarb, radish, early salad. |
|
Short season Zones 2-3 |
Peas, carrots, radish, spinach early month; beans and corn very late month under cover. | Nothing new. | Tomatoes, peppers and squash only after the last frost — late May. | Rhubarb, first radish and salad. |
May garden jobs
- Confirm your last frost date before transplanting anything tender.
- Use black plastic mulch or low tunnels to lift soil temperature for warm crops.
- Harden off thoroughly — a week to ten days minimum.
- Water transplants in well and keep them watered while establishing.
- Thin direct-sown rows promptly; crowded roots never size up in a short season.
Common May mistakes
- Planting out on the May long weekend regardless of the actual forecast, which is the single most common Canadian gardening loss.
- Direct sowing beans or corn into 8°C soil, where seed rots.
- Skipping black plastic on the Prairies, where soil warmth is the binding constraint on cucurbits and corn.
- Forgetting that a clear, still night after a warm day is when frost actually lands.
Turn May's jobs into a written plan. The Canada Vegetable Garden Planner (printable PDF) has frost-date planning pages, bed layouts, crop rotation, a sowing log and a harvest tracker — 70 printable pages.
More Canada planting guides
- What to plant in April Canada
- What to plant in June Canada
- Vegetable Planting Calendar Canada
- Vegetable Growing Guides for Canada
Frequently Asked Questions
When is it safe to plant tomatoes in Canada?
After your local last frost: around late April to early May on the coast, mid-May in southern Ontario, early May in Montreal, and around 23-25 May in Calgary and Winnipeg. Wait for nights above 10°C as well as the frost date.
What soil temperature do beans need in Canada?
At least 10°C, and ideally 15°C. Below that, bean seed rots before it germinates — a very common Prairie failure.
Should I use black plastic mulch?
On the Prairies and anywhere with cold spring soil, yes. It commonly lifts soil temperature by several degrees and can be the difference between a corn crop and no corn crop.
Plan your May beds
Turn this month's list into a layout: sketch your plot in the free Garden Layout Planner, then follow the whole season with the Canada Vegetable Garden Planner (printable PDF, 70 pages). For the full year, see the Canada vegetable planting calendar, browse every crop in the Canada growing guides, or use the Canada site directory.
Last updated 25 August 2026
Turn This Month's Jobs Into A Plan
Month-by-month advice works best when it becomes a written sowing list, bed plan, and follow-up task list.
Keep going
Plan the next step
Use the printable SoilCommander planner for your region to turn this guide into sowing dates, bed layouts and weekly garden tasks.