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

You will be able to determine when to plant radicchio by referring to the USDA zone info for Ottawa.

Planting Calendar for Radicchio

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

Radicchio do well in moderate cold which tells us that you can get them planted earlier than other frost tender plants.

The earliest that you can plant radicchio 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 radicchio and expect a good harvest is probably September. You probably don't want to wait any later than that or else your radicchio may not have a chance to fully mature. Starting your radicchio indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Ottawa is just an average the actual date of last frost is different every year. Since half of the time in Ottawa last frost occurs after April 15 be ready to cover your radicchio if you have a surprise 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.