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 getting a good idea when it's the best time to plant fennel is to consult the USDA zone info for Iron Mountain.

Planting Calendar for Fennel

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

Fennel do well in cold which tells us that you can plant them a quite a bit earlier than more sensitive plants.

The earliest that you can plant fennel in Iron Mountain 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. If you wait any later than that and your fennel may not have a chance to fully mature. 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 May 15 in Iron Mountain. In the coldest months of winter you can expect an average low temperature of -30°F.

It's important to remember that USDA zone info for Iron Mountain is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Iron Mountain you get a frost after May 15 be ready to protect your fennel if you have a surprise late frost.

USDA Zone Info for Iron Mountain

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 Iron Mountain

You may be interested in your other planting guides for Iron Mountain.