One of the first steps you take when you are determining your gardening schedule is find your 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.

It's a good idea to figure out when it's the best time to plant black radish by referring to the USDA zone info for Ottawa.

Planting Calendar for Black radish

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

You can plant black radish a little earlier in the year because they are moderately cold tolerant.

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

Last Frost Date

The average date of last frost is April 15 in Ottawa. You should expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Ottawa is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Ottawa you get a frost after April 15 be ready to cover your black radish in the event of 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.