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.

The first opportunity to plant fennel in Rock Falls should be determined 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 do ok in cold weather which tells us that you can plant them much earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant fennel in Rock Falls 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. You probably don't want to wait any later than that or else your fennel may not have a chance to grow to maturity. You can get started a little bit earlier by starting your fennel indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Rock Falls. In the coldest months of winter you can expect an average low temperature of -15°F.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Rock Falls and it can change quite a bit from year to year. Half of the time in Rock Falls you get surprised by a frost after April 15 so make sure that you are ready to protect your fennel in the event of one of those late frosts.

USDA Zone Info for Rock Falls

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Rock Falls

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