One of the best tools that you have as gardeners to help us estimate 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.

The USDA zone info for Ontario can be looked at to estimate when it's a good idea to plant scarlet pimpernels.

Planting Calendar for Scarlet Pimpernels

Frost tolerance for scarlet pimpernels:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Scarlet Pimpernels are barely cold tolerant which means that you can plant them slightly earlier than plants that are more sensitive to the cold.

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

The last month that you can plant scarlet pimpernels and expect a good harvest is probably August. Any later than that and your scarlet pimpernels may not have a chance to really do well. You can get started a few weeks earlier by starting your scarlet pimpernels indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Ontario. It might get as low as -15°F during the coldest months of winter.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Ontario and it is different every year. Since half of the time in Ontario you get a frost after April 15 be ready to cover your scarlet pimpernels if you have 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.