One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to determine when you can plant celery by looking at the USDA zone info for Ontario.

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.

Since celery are one of those plants that can tolerate a tiny bit of cold weather you can plant them slightly earlier in the year than other plants that might not handle the cold.

The earliest that you can plant celery in Ontario 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 celery and expect a good harvest is probably September. Any later than that and your celery may not have a chance to grow to maturity. Starting your celery indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Ontario the average date of last frost happens on January 31. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for Ontario is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Ontario there is a last frost after January 31 be ready to protect your celery in the event of one of those late frosts.

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.