One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

In River Rouge you can figure out 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.

You can plant fennel a lot earlier in the year because they are very cold tolerant.

The earliest that you can plant fennel in River Rouge 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 grow to maturity. If you are starting your fennel indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In River Rouge the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -5°F.

Remember that USDA zone info for River Rouge is just an average and the actual date of last frost is different every year. Since half of the time in River Rouge there is a last frost after April 15 be ready to cover your fennel in the event of one of those late frosts.

USDA Zone Info for River Rouge

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 River Rouge

You may be interested in your other planting guides for River Rouge.