One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. 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 sweet sultan in Knoxville should be estimated by using the USDA zone info.

Planting Calendar for Sweet Sultan

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

Sweet Sultan do ok in moderate cold which tells us that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant sweet sultan in Knoxville 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 sweet sultan and expect a good harvest is probably August. Any later than that and your sweet sultan may not have a chance to really do well. If you are starting your sweet sultan indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Knoxville. In the coldest months of winter you can 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 will vary from year to year. Half of the time in Knoxville last frost occurs after April 15 so be sure to be ready to cover your sweet sultan in the event of 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.