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

The best time to plant osteospermum in Ottawa should be determined by looking at the USDA zone info.

Planting Calendar for Osteospermum

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

You can plant osteospermum a bit earlier in the year because they are moderately cold tolerant.

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

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Ottawa. 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 changes from year to year. Half of the time in Ottawa you get a frost after April 15 so be sure to be ready to cover your osteospermum if you have 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.