The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant cauliflower in Ottawa can be estimated by using the USDA zone info.

Planting Calendar for Cauliflower

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

You can plant cauliflower a little 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 cauliflower 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 cauliflower and expect a good harvest is probably September. You probably don't want to wait any later than that or else your cauliflower may not have a chance to fully mature. You can get started a little bit earlier by starting your cauliflower indoors.

Last Frost Date

The average date of last frost is April 15 in Ottawa. It might get as low as -15°F during the coldest months of winter.

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Ottawa and it changes from year to year. Half of the time in Ottawa it frosts late in the year after April 15 so make sure that you are prepared to cover your cauliflower in the event of a late frost.

USDA Zone Info for Ottawa

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 Ottawa

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