One of the best tools that you have as gardeners to help us figure out 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.

A common way of estimating when it's the best time to plant fennel is to refer to the USDA zone info for Duluth.

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 means that you can start planting them much earlier than other frost tender plants.

The earliest that you can plant fennel in Duluth 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. You probably don't want to wait any later than that or else your fennel may not have a chance to really do well. Starting your fennel indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Duluth the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Remember that USDA zone info for Duluth is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Duluth 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 Duluth

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°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 -25°F.

Plants to Grow in Duluth

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