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.

By using the USDA zone info for Ontario you will be able to figure out when it's the best time to plant celery.

Planting Calendar for Celery

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

Celery do ok in moderate cold which means that you can get them planted just a bit earlier than other frost tender plants.

The earliest that you can plant celery in Ontario 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 celery and expect a good harvest is probably August. Any later than that and your celery may not have a chance to fully mature. You can get started a few weeks earlier by starting your celery indoors.

Last Frost Date

In Ontario the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Ontario and it changes from year to year. Since half of the time in Ontario last frost occurs after April 15 be ready to protect your celery in the event of 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.