The USDA Zone info is a great tool for gardeners to help us figure out 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.

The USDA zone info for Ontario can be reffered to in order to figure out when it's a good idea to plant pennyroyal.

Planting Calendar for Pennyroyal

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

You can plant pennyroyal much earlier in the year because they do well in cold.

The earliest that you can plant pennyroyal 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 pennyroyal and expect a good harvest is probably September. Any later than that and your pennyroyal may not have a chance to grow to maturity. Starting your pennyroyal indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Ontario and it will vary from year to year. Since half of the time in Ontario you get a frost after April 15 be ready to protect your pennyroyal if you have a surprise 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.