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

By looking at the USDA zone info for Ontario it's possible to figure out when it's a good idea to plant lobelia.

Planting Calendar for Lobelia

Frost tolerance for lobelia:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since lobelia are very cold tolerant you can plant them much earlier in the year than more sensitive plants.

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

Last Frost Date

On average the last frost is on April 15 in Ontario. In the coldest months of winter you can expect an average low temperature of -5°F.

It's important to remember that USDA zone info for Ontario is not always accurate and 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 April 15 so always be ready to cover your lobelia if you have a late frost.

USDA Zone Info for Ontario

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Ontario

You may be interested in your other planting guides for Ontario.