One of the best tools that you have as gardeners to help us determine 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 way of figuring out when it's a good idea to plant bidens is to examine the USDA zone info for Rock Falls.

Planting Calendar for Bidens

Frost tolerance for bidens:	Not tolerant of frost.
When to plant:	After the last frost.

Bidens are not cold tolerant which tells us that it's necessary to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant bidens in Rock Falls is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant bidens and expect a good harvest is probably August. You probably don't want to wait any later than that or else your bidens may not have a chance to really do well. You can get started a few weeks earlier by starting your bidens indoors.

Last Frost Date

In Rock Falls the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Rock Falls and it changes from year to year. Since half of the time in Rock Falls you get a frost after April 15 be ready to cover your bidens 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.