Before planting it is a good idea to find your USDA Zone info to determine 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.

In Rapid City you can estimate when it's a good idea to plant pentas by using the USDA zone info.

Planting Calendar for Pentas

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

It's probably not a good idea to plant pentas until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant pentas 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 pentas and expect a good harvest is probably August. Any later than that and your pentas may not have a chance to really do well. Starting your pentas indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Rapid City. In the coldest months of winter you can expect an average low temperature of -20°F.

Just be sure to remember that USDA zone info for Rapid City may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Rapid City there is a last frost after April 15 be ready to protect your pentas 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.