One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant heliotrope in Knoxville can be figured out by using the USDA zone info.

Planting Calendar for Heliotrope

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

It's probably a bad idea to plant heliotrope until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant heliotrope 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 heliotrope and expect a good harvest is probably August. You probably don't want to wait any later than that or else your heliotrope may not have a chance to really do well. Starting your heliotrope indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Just be sure to remember that USDA zone info for Knoxville may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Knoxville you get surprised by a frost after April 15 so make sure that you are ready to protect your heliotrope if you have one of those late frosts.

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.