One of the best tools that you have as gardeners to help us figure out 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.

In Ontario you can figure out when it's the best time to plant catharanthus by referring to the USDA zone info.

Planting Calendar for Catharanthus

Frost tolerance for catharanthus:	Not tolerant of frost.
When to plant:	After the last frost.

You really shouldn't plant catharanthus until after the last frost has passed because they do not do well in cold weather.

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

Last Frost Date

On average the last frost is on January 31 in Ontario. In the coldest months of winter you should expect an average low temperature of 30°F.

Remember that the actual date of last frost is 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 cover your catharanthus in the event of 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.