Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Ontario you can determine when it's possible to plant kohlrabi by looking at the USDA zone info.

Planting Calendar for Kohlrabi

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

Since kohlrabi are moderately cold tolerant you can plant them a little bit earlier in the year than other frost tender plants.

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

Last Frost Date

On average the last frost has passed is on April 15 in Ontario. You should expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Ontario is an average the actual date of last frost changes from year to year. Since half of the time in Ontario you get a frost after April 15 be ready to cover your kohlrabi in the event of a surprise 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.