The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of getting a good idea when it's the best time to plant lisianthus is to refer to the USDA zone info for Knoxville.

Planting Calendar for Lisianthus

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

It's a bad idea to plant lisianthus until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant lisianthus in Knoxville 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 grow to maturity. You can get started a couple of weeks earlier by starting your lisianthus indoors.

Last Frost Date

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

Keep in mind that USDA zone info for Knoxville is an average and the actual date of last frost will vary from year to year. Half of the time in Knoxville there is a last frost after April 15 so just be sure to be ready to protect your lisianthus in the event of a surprise late frost.

USDA Zone Info for Knoxville

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 Knoxville

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