The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to figure out when to plant calendula by checking out the USDA zone info for Knoxville.

Planting Calendar for Calendula

Frost tolerance for calendula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Calendula are one of those plants that can tolerate a little bit of cold weather which means that you can get them planted earlier than other frost tender plants.

The earliest that you can plant calendula in Knoxville is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant calendula and expect a good harvest is probably September. Any later than that and your calendula may not have a chance to grow to maturity. Starting your calendula indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Knoxville. In the coldest months of winter you can expect an average low temperature of -15°F.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Knoxville and it 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 always be ready to protect your calendula if you have 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.