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.

In Detroit you can estimate when it's the best time to plant fennel by referring to the USDA zone info.

Planting Calendar for Fennel

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

Since fennel do well in cold you can plant them a lot earlier in the year than other plants that might not handle the cold.

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

Last Frost Date

The average date of last frost is April 15 in Detroit. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Detroit may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Detroit last frost occurs after April 15 be ready to cover your fennel in the event of a late frost.

USDA Zone Info for Detroit

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 Detroit

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