One of the first steps you take when you are estimating 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.

The USDA zone info for Ontario should be used to determine when to plant impatiens.

Planting Calendar for Impatiens

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

It's a bad idea to plant impatiens until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant impatiens 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 impatiens and expect a good harvest is probably September. Any later than that and your impatiens may not have a chance to grow to maturity. If you are starting your impatiens indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is January 31 in Ontario. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for Ontario is an average the actual date of last frost will vary from year to year. Since half of the time in Ontario it frosts late in the year after January 31 be ready to cover your impatiens in the event of one of those late frosts.

USDA Zone Info for Ontario

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Ontario

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