One of the first steps you take when you are making a decision about 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.

The best time to plant datura in Ottawa should be estimated by using the USDA zone info.

Planting Calendar for Datura

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

Datura are one of those plants that can tolerate a tiny bit of cold weather which means that you can get them planted just a bit earlier than other frost tender plants.

The earliest that you can plant datura 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 datura and expect a good harvest is probably August. Any later than that and your datura may not have a chance to really do well. Starting your datura 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. It might get as low as -10°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Ottawa is an average and the actual date of last frost changes from year to year. Half of the time in Ottawa it frosts late in the year after April 15 so just be sure to be ready to cover your datura if you have a surprise 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.