Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when it's possible to plant fennel in Casper by using 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 very cold tolerant which tells us that you can plant them much earlier than more sensitive plants.

The earliest that you can plant fennel in Casper 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. If you wait any later than that and your fennel may not have a chance to grow to maturity. Starting your fennel indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Casper. You should expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Casper is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Casper you get a frost after April 15 so just be sure to be ready to cover your fennel in the event of one of those late frosts.

USDA Zone Info for Casper

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Casper

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