Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to figure out when to plant calibrachoa by referring to the USDA zone info for Ontario.

Planting Calendar for Calibrachoa

Frost tolerance for calibrachoa:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Calibrachoa are one of those plants that can tolerate a tiny bit of cold weather which means that you can get them planted just a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant calibrachoa in Ontario is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant calibrachoa and expect a good harvest is probably August. You probably don't want to wait any later than that or else your calibrachoa may not have a chance to really do well. You can get started a couple of weeks earlier by starting your calibrachoa indoors.

Last Frost Date

The average date of last frost is April 15 in Ontario. You should expect an average low temperature of -5°F in the coldest months of winter.

Always keep in mind that USDA zone info for Ontario is just an average and the actual date of last frost is different every year. Since half of the time in Ontario you get surprised by a frost after April 15 be ready to cover your calibrachoa in the event of a late frost.

USDA Zone Info for Ontario

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 Ontario

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