One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of determining when it's a good idea to plant tithonia is to look at the USDA zone info for Ontario.

Planting Calendar for Tithonia

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

Tithonia require warm weather which means that you need to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

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

Last Frost Date

The average date of last frost is January 31 in Ontario. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for Ontario is not always accurate the actual date of last frost will vary from year to year. Half of the time in Ontario you get surprised by a frost after January 31 so always be ready to cover your tithonia if you have 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.