Before planting it is a good idea to find your USDA Zone info to determine 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 first chance to plant coreopsis in Ontario can be figured out by using the USDA zone info.

Planting Calendar for Coreopsis

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

Coreopsis do well in moderate cold which tells us that you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

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

The last month that you can plant coreopsis and expect a good harvest is probably October. You probably don't want to wait any later than that or else your coreopsis may not have a chance to grow to maturity. If you are starting your coreopsis indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in Ontario. It might get as low as 30°F during the coldest months of winter.

Always keep in mind that USDA zone info for Ontario is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Ontario you get surprised by a frost after January 31 so make sure that you are prepared to cover your coreopsis in the event of a surprise late frost.

USDA Zone Info for Ontario

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Ontario

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