One of the first steps you take when you are figuring out 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 Toronto you can estimate when you can plant nierembergia by reviewing the USDA zone info.

Planting Calendar for Nierembergia

Frost tolerance for nierembergia:	Not tolerant of frost.
When to plant:	After the last frost.

Nierembergia require warm weather which means that you need to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant nierembergia in Toronto 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 nierembergia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your nierembergia may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your nierembergia indoors.

Last Frost Date

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

Since the USDA zone info for Toronto may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Toronto there is a last frost after April 15 be ready to cover your nierembergia in the event of one of those late frosts.

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.