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

You can estimate when it's a good idea to plant bok choi in Ontario by looking at the USDA zone info.

Planting Calendar for Bok Choi

Frost tolerance for bok choi:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant bok choi just a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant bok choi 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 bok choi and expect a good harvest is probably September. If you wait any later than that and your bok choi may not have a chance to really do well. Starting your bok choi indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Ontario and it can change quite a bit from year to year. Half of the time in Ontario you get surprised by a frost after April 15 so make sure that you are prepared to cover your bok choi 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.