The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Toronto you can figure out when you can plant onions by looking at the USDA zone info.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Onions tend to make it in pretty solid cold which means that you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant onions in Toronto is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant onions and expect a good harvest is probably September. You probably don't want to wait any later than that or else your onions may not have a chance to grow to maturity. If you are starting your onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Toronto. It might get as low as -5°F during the coldest months of winter.

It's important to remember that USDA zone info for Toronto is not always accurate and the actual date of last frost changes from year to year. Half of the time in Toronto there is a last frost after April 15 so be sure to be ready to cover your onions in the event of a late frost.

USDA Zone Info for Toronto

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Toronto

You may be interested in your other planting guides for Toronto.