The USDA Zone info is a great tool for gardeners to help us determine 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.

The USDA zone info for Knoxville can be reffered to in order to figure out when it's the best time to plant primula.

Planting Calendar for Primula

Frost tolerance for primula:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since primula do well in cold you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant primula 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 primula and expect a good harvest is probably September. If you wait any later than that and your primula may not have a chance to grow to maturity. Starting your primula indoors is a great way to get them started a couple of weeks earlier.

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 0°F.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Knoxville and it can change quite a bit from year to year. Since half of the time in Knoxville you get surprised by a frost after April 15 be ready to cover your primula in the event of one of those late frosts.

USDA Zone Info for Knoxville

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Knoxville

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