Before planting it is a good idea to find your USDA Zone info to estimate 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.

You will be able to determine when to plant celosia by looking at the USDA zone info for Ontario.

Planting Calendar for Celosia

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

It's probably not a good idea to plant celosia until after the last frost because they are not cold tolerant.

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

Last Frost Date

On average all chance of frost has passed is on April 15 in Ontario. In the coldest months of winter you should expect an average low temperature of -5°F.

Keep in mind that USDA zone info for Ontario may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in Ontario there is a last frost after April 15 be ready to cover your celosia if you have one of those late frosts.

USDA Zone Info for Ontario

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Ontario

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