Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Dubuque should be used to determine when it's a good idea to plant fennel.

Planting Calendar for Fennel

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

Since fennel do well in cold you can plant them quite a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant fennel in Dubuque 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. Any later than that and your fennel may not have a chance to fully mature. Starting your fennel indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Dubuque the average date of last frost happens on April 15. You can expect an average low temperature of -20°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Dubuque and it changes from year to year. Half of the time in Dubuque you get surprised by a frost after April 15 so always be ready to protect your fennel if you have a surprise late frost.

USDA Zone Info for Dubuque

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 Dubuque

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