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.

The first chance to plant platycodon in Ontario should be figured out by checking out the USDA zone info.

Planting Calendar for Platycodon

Frost tolerance for platycodon:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Platycodon do ok in a tiny bit of cold which tells us that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant platycodon in Ontario is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant platycodon and expect a good harvest is probably August. You probably don't want to wait any later than that or else your platycodon may not have a chance to fully mature. You can get started a few weeks earlier by starting your platycodon indoors.

Last Frost Date

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

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Ontario and it changes from year to year. Since half of the time in Ontario you get surprised by a frost after April 15 be ready to protect your platycodon if you have a surprise late frost.

USDA Zone Info for Ontario

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Ontario

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