Toronto, Canada · 43.65°
When to plant marigolds in Toronto
The Toronto dates are calculated from the observed last spring frost — a 2016–2025 mean of 25 April — rather than from a latitude estimate or a national calendar. The frost-free season here averages 197 days.
Season anchorobserved 2016–2025
Last spring frost: 25 April · latest 15 May
First autumn frost: 8 November · earliest 30 Oct
Frost-free season: 197 days · 10 complete years
These come from the ERA5 reanalysis on a roughly 9 km grid, so they describe the area rather than your plot. A hollow, a frost pocket or an exposed site regularly runs several degrees colder, so use the cautious date for a decision you cannot undo.
Frost date estimator →Local calendar windows
The cautious column is calculated from the latest frost recorded in the period (15 May). Use it for tender crops you cannot re-sow.
The year in Toronto
What can move the date
The most useful companion plant in a vegetable garden: French marigolds suppress root-knot nematodes in the soil and draw hoverflies that clear aphids. Plant them among the tomatoes, not in a separate border.
Final spacing: 20 × 30 cm. Soil: pH 6–7.5.
Direct-sow only once the soil holds 15°C or more — soil temperature decides germination, not the date.
Problems in Toronto
Each has its locally favourable conditions counted month by month, from the weather archive for this city.
Full guide: marigolds diseases and pests →