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.

In Rapid City you can figure out when you can plant trifolium by reviewing the USDA zone info.

Planting Calendar for Trifolium

Frost tolerance for trifolium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Trifolium are barely cold tolerant which tells us that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant trifolium in Rapid City is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant trifolium and expect a good harvest is probably August. If you wait any later than that and your trifolium may not have a chance to really do well. You can get started a little bit earlier by starting your trifolium indoors.

Last Frost Date

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

Since the USDA zone info for Rapid City is an average the actual date of last frost will vary from year to year. Half of the time in Rapid City you get surprised by a frost after April 15 so make sure that you are ready to cover your trifolium 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.