One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Ontario you can estimate when it's possible to plant spearmint by checking out the USDA zone info.

Planting Calendar for Spearmint

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

You can plant spearmint a lot earlier in the year because they do well in cold.

The earliest that you can plant spearmint in Ontario 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 spearmint and expect a good harvest is probably September. Any later than that and your spearmint may not have a chance to fully mature. Starting your spearmint indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Ontario. You should expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Ontario is not always accurate the actual date of last frost is different every year. Half of the time in Ontario you get surprised by a frost after April 15 so always be ready to protect your spearmint in the event of a late frost.

USDA Zone Info for Ontario

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 Ontario

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