Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Spearfish should be reffered to in order to determine when it's the best time to plant lisianthus.

Planting Calendar for Lisianthus

Frost tolerance for lisianthus:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since lisianthus do not do well in cold weather you must wait until after the last frost has passed before you can plant them.

The earliest that you can plant lisianthus in Spearfish 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 lisianthus and expect a good harvest is probably August. If you wait any later than that and your lisianthus may not have a chance to fully mature. If you are starting your lisianthus indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Spearfish may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Spearfish you get a frost after April 15 so just be sure to be ready to cover your lisianthus in the event of a late frost.

USDA Zone Info for Spearfish

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 Spearfish

You may be interested in your other planting guides for Spearfish.