What to Plant in May Canada

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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 10-15C.

SoilCommander Editorial Team

Canada vegetable growing guides · Checked against Agriculture and Agri-Food Canada plant hardiness data

Every Canadian growing guide is written and maintained by our editorial team for real Canadian growing conditions, and checked against Agriculture and Agri-Food Canada hardiness and frost-date data and provincial agriculture guidance before publication.

May 3-25

Last frost: Montreal to Winnipeg

10C

Soil minimum for beans

15-16C

Soil minimum for squash and corn

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 8C 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

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 10C as well as the frost date.

What soil temperature do beans need in Canada?

At least 10C, and ideally 15C. 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.

Last updated 25 August 2026

Relevant next steps

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.

Printable garden plannerRecord this month's sowing dates, crop rotation, and bed tasks. Seed starting setupChoose trays, labels, compost, and indoor sowing tools before you start. Full planting calendarCompare this month with the rest of the UK growing year.

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.

Get Planner

What to Plant in May Canada