The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant saxifraga in Ottawa can be determined by using the USDA zone info.

Planting Calendar for Saxifraga

Frost tolerance for saxifraga:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since saxifraga are one of those plants that can tolerate a tiny bit of cold weather you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant saxifraga in Ottawa is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant saxifraga and expect a good harvest is probably August. You probably don't want to wait any later than that or else your saxifraga may not have a chance to really do well. Starting your saxifraga indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Ottawa the average date of last frost happens on April 15. You can 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 will vary from year to year. Half of the time in Ottawa you get surprised by a frost after April 15 so always be ready to protect your saxifraga 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.