One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to estimate when it's the best time to plant bidens by referring to the USDA zone info for Rapid City.

Planting Calendar for Bidens

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

It's probably a bad idea to plant bidens until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant bidens in Rapid City 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. If you wait any later than that and your bidens may not have a chance to grow to maturity. If you are starting your bidens indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Since the USDA zone info for Rapid City is not always accurate the actual date of last frost is different every year. Half of the time in Rapid City last frost occurs after April 15 so make sure that you are ready to protect your bidens in the event of one of those late frosts.

USDA Zone Info for Rapid City

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 Rapid City

You may be interested in your other planting guides for Rapid City.