One of the first steps you take when you are figuring out your gardening schedule is find your 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.

You can determine when it's a good idea to plant bidens in Castle Rock by referring to the USDA zone info.

Planting Calendar for Bidens

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

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 Castle Rock 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 little bit earlier by starting your bidens indoors.

Last Frost Date

The average date of last frost is April 15 in Castle Rock. 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 not always accurate because it is based on the USDA zone info for Castle Rock and it is different every year. Half of the time in Castle Rock you get surprised by a frost after April 15 so be sure to be ready to cover your bidens if you have one of those late frosts.

USDA Zone Info for Castle Rock

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 Castle Rock

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