One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant fennel in Zone 4b can be figured out by checking out 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.

Fennel are one of those plants that can tolerate quite a bit of cold weather which tells us that you can plant them much earlier than more sensitive plants.

The earliest that you can plant fennel in Zone 4b 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 fennel and expect a good harvest is probably August. 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

In Zone 4b the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -25°F.

Keep in mind that USDA zone info for Zone 4b is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Zone 4b you get surprised by a frost after May 15 be ready to protect your fennel in the event of a surprise late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.