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

It's possible to determine when you can plant flower-of-an-hour by reviewing the USDA zone info for Ottawa.

Planting Calendar for Flower-of-an-Hour

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

You can plant flower-of-an-hour just a tiny bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant flower-of-an-hour 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 flower-of-an-hour and expect a good harvest is probably August. If you wait any later than that and your flower-of-an-hour may not have a chance to really do well. You can get started a couple of weeks earlier by starting your flower-of-an-hour indoors.

Last Frost Date

In Ottawa the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

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 a frost after April 15 so always be ready to protect your flower-of-an-hour if you have a late frost.

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.