One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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 possible to determine when to plant platycodon by reviewing the USDA zone info for Ontario.

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 tend to make it in a tiny bit of cold which means that you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant platycodon 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 platycodon and expect a good harvest is probably September. You probably don't want to wait any later than that or else your platycodon may not have a chance to really do well. If you are starting your platycodon indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Ontario may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Ontario you get a frost after January 31 be ready to cover your platycodon if you have 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.