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

One way of getting a good idea when it's a good idea to plant cleome is to refer to the USDA zone info for Ontario.

Planting Calendar for Cleome

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

Cleome require warm weather which tells us that it's important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant cleome 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 cleome and expect a good harvest is probably September. If you wait any later than that and your cleome may not have a chance to really do well. If you are starting your cleome indoors then you might be able to get away with starting them a few weeks earlier.

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 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 January 31 so be sure to be ready to cover your cleome 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.