Seasonal Action Guide
What to Do in the Garden in March (Canada)
The short answer
For most Canadian gardeners the headline March task is peppers: start them indoors about 10 weeks before your last frost date, which for a mid-to-late-May frost-free date lands in early-to-mid March. It is still too early for tomatoes in zones 3-5 — they go in about 8 weeks before frost, usually early April on the Prairies. March is also the month to test viability of older seed packets and to prune fruit trees while they are dormant.
Outdoors, patience is the task. Stay off snow-covered or waterlogged beds to avoid compacting the soil, and let mulch stay in place — freeze-thaw cycles in March can heave and damage perennials that are uncovered too early.
Start and sow (indoors)
- Start peppers indoors about 10 weeks before your last frost date — early-to-mid March for a mid-to-late-May frost-free date.
- Check germination on old seed packets now, while there is still time to reorder.
- Keep February-started onions, celery, and herbs under lights, and keep sowing microgreens and lettuce.
Prune and prepare
- Prune fruit trees while dormant (late winter is the recommended window on the Prairies).
- Clean, sharpen, and repair tools and the mower before the spring rush (a Toronto Master Gardeners spring-prep task).
- Map this year's beds and plan crop rotation while everything is still on paper.
Maintain and protect
- Do not walk on snow-covered or saturated garden beds — compaction damages soil structure for the whole season.
- Leave winter mulch on perennials and strawberries; March freeze-thaw cycles can heave exposed crowns.
- Keep feeding winter birds until natural food sources return.
Regional notes
South coastal BC is the exception to Canada's frozen March: with an average last frost around March 28 (West Coast Seeds), coastal gardeners can direct-sow hardy vegetables and are weeks into their outdoor season while the Prairies and central Canada are still under snow. Prairie, Ontario, Quebec, and Maritime gardeners should keep to indoor sowing and dormant pruning.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- Gardening at USask — Gardening Timeline (March) — March tasks: start peppers 10 weeks before last frost, check seed viability, prune fruit trees, avoid walking on snow-covered beds
- Toronto Master Gardeners — Spring Clean-up Guide — Early-spring tool cleaning/sharpening and early pruning before new growth; observe garden microclimates during spring cleanup
- West Coast Seeds — Regional Planting Charts (Coastal BC) — South coastal BC average last frost around March 28, enabling much earlier outdoor sowing than the rest of Canada
Keep going
Garden Tasks for January (Warm-Climate US)
Seasonal Action Guide
Garden Tasks for February (Warm-Climate US)
Seasonal Action Guide
Garden Tasks for March (Warm-Climate US)
Seasonal Action Guide
Garden Tasks for April (Canada)
Seasonal Action Guide
Garden Tasks for February (Canada)
Seasonal Action Guide
Garden Tasks for March (Cool-Climate US)
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Garden Tasks for August (Canada)
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Garden Tasks for December (Canada)
Seasonal Action Guide