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

The best time to plant nierembergia in Knoxville should be estimated by checking out the USDA zone info.

Planting Calendar for Nierembergia

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

It's a bad idea to plant nierembergia until after the last frost has passed because they are not cold tolerant.

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

Last Frost Date

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

Since the USDA zone info for Knoxville may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Knoxville you get a frost after April 15 be ready to cover your nierembergia in the event of a 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.