One of the first steps you take when you are making a decision about 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.

It's a good idea to determine when to plant heliotrope by using the USDA zone info for Ontario.

Planting Calendar for Heliotrope

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

Since heliotrope require warm weather it's necessary to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant heliotrope 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 heliotrope and expect a good harvest is probably September. If you wait any later than that and your heliotrope may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your heliotrope indoors.

Last Frost Date

In Ontario the average date of last frost happens on January 31. You can expect an average low temperature of 30°F in 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. Since half of the time in Ontario there is a last frost after January 31 be ready to protect your heliotrope in the event of a surprise 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.