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.

By using the USDA zone info for Ontario it's possible to figure out when to plant radicchio.

Planting Calendar for Radicchio

Frost tolerance for radicchio:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Radicchio do ok in a little bit of cold which means that you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

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

The last month that you can plant radicchio and expect a good harvest is probably October. If you wait any later than that and your radicchio may not have a chance to really do well. You can get started a little bit earlier by starting your radicchio indoors.

Last Frost Date

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

Since the USDA zone info for Ontario is an average the actual date of last frost changes from year to year. Half of the time in Ontario there is a last frost after January 31 so make sure that you are ready to cover your radicchio if you have a 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.