One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of determining when it's possible to plant fennel is to examine the USDA zone info for Ontario.

Planting Calendar for Fennel

Frost tolerance for fennel:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Fennel do ok in cold weather which tells us that you can plant them quite a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant fennel 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 fennel and expect a good harvest is probably October. Any later than that and your fennel may not have a chance to grow to maturity. If you are starting your fennel indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is January 31 in Ontario. 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 changes from year to year. Since half of the time in Ontario you get a frost after January 31 be ready to protect your fennel in the event of a 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.