One of the first steps you take when you are getting a good idea your gardening schedule is find your 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 should be used to determine when you can plant sweet potatos.

Planting Calendar for Sweet Potatos

Frost tolerance for sweet potatos:	Not tolerant of frost.
When to plant:	After the last frost has passed.

You should not plant sweet potatos until after the last frost because they do not do well in cold weather.

The earliest that you can plant sweet potatos 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 sweet potatos and expect a good harvest is probably September. Any later than that and your sweet potatos may not have a chance to fully mature. If you are starting your sweet potatos 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. You can expect an average low temperature of 30°F in the coldest months of winter.

Since the USDA zone info for Ontario is an average the actual date of last frost changes from year to year. Since half of the time in Ontario you get a frost after January 31 be ready to cover your sweet potatos 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.