One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of determining when to plant perilla is to refer to the USDA zone info for Ontario.

Planting Calendar for Perilla

Frost tolerance for perilla:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since perilla require warm weather you need to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant perilla in Ontario is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant perilla and expect a good harvest is probably August. If you wait any later than that and your perilla may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your perilla indoors.

Last Frost Date

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

Since the USDA zone info for Ontario may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Ontario it frosts late in the year after April 15 so just be sure to be ready to cover your perilla in the event of a surprise late frost.

USDA Zone Info for Ontario

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Ontario

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