The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to figure out when to plant fennel by referring to the USDA zone info for Great Falls.

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 means that you can get them planted much earlier than plants that are more sensitive to the cold.

The earliest that you can plant fennel in Great Falls 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 really do well. Starting your fennel indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Great Falls. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Great Falls may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Great Falls you get surprised by a frost after May 15 be ready to cover your fennel if you have a late frost.

USDA Zone Info for Great Falls

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 Great Falls

You may be interested in your other planting guides for Great Falls.