Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Ontario can be reffered to in order to determine when to plant nemesia.

Planting Calendar for Nemesia

Frost tolerance for nemesia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably not a good idea to plant nemesia until after the last frost has passed because they require warm weather.

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

The last month that you can plant nemesia and expect a good harvest is probably August. If you wait any later than that and your nemesia may not have a chance to grow to maturity. If you are starting your nemesia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Ontario the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Ontario and it is different every year. Since half of the time in Ontario there is a last frost after April 15 be ready to cover your nemesia if you have a late frost.

USDA Zone Info for Ontario

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Ontario

You may be interested in your other planting guides for Ontario.