The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant cuphea in Ontario can be estimated by referring to the USDA zone info.

Planting Calendar for Cuphea

Frost tolerance for cuphea:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

You should not plant cuphea until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant cuphea in Ontario 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 cuphea and expect a good harvest is probably August. If you wait any later than that and your cuphea may not have a chance to fully mature. Starting your cuphea indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Ontario the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Ontario is just an average the actual date of last frost is different every year. Half of the time in Ontario there is a last frost after April 15 so be sure to be ready to protect your cuphea in the event of 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.