Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant coreopsis in Ottawa can be estimated by reviewing 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.

Since coreopsis are moderately cold tolerant you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant coreopsis 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 coreopsis and expect a good harvest is probably September. You probably don't want to wait any later than that or else your coreopsis may not have a chance to really do well. Starting your coreopsis indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Ottawa may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Ottawa you get surprised by a frost after April 15 so make sure that you are ready to cover your coreopsis 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.