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.

One way of figuring out when it's the best time to plant corn is to examine the USDA zone info for Ontario.

Planting Calendar for Corn

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

It's probably not a good idea to plant corn until after the last frost because they are not cold tolerant.

The earliest that you can plant corn 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 corn and expect a good harvest is probably September. Any later than that and your corn may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your corn indoors.

Last Frost Date

In Ontario the average date of last frost happens on January 31. In the coldest months of winter you can expect an average low temperature of 30°F.

It's important to remember that the actual date of last frost is just 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 last frost occurs after January 31 be ready to protect your corn in the event of a surprise late frost.

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.