One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of figuring out when it's the best time to plant kohlrabi is to use the USDA zone info for Ottawa.

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 Ottawa 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. Any later than that and your kohlrabi may not have a chance to fully mature. If you are starting your kohlrabi indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Ottawa the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

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 Ottawa and it can change quite a bit from year to year. Since half of the time in Ottawa last frost occurs after April 15 be ready to cover your kohlrabi if you have one of those late frosts.

USDA Zone Info for Ottawa

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Ottawa

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