One of the first steps you take when you are getting a good idea your gardening schedule is find your 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.

You can determine when you can plant primula in Louisville by reviewing the USDA zone info.

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 quite a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant primula in Louisville 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. You can get started a little bit earlier by starting your primula indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Louisville. 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 not always accurate because it is based on the USDA zone info for Louisville and it is different every year. Half of the time in Louisville it frosts late in the year after April 15 so make sure that you are prepared to protect your primula in the event of a surprise late frost.

USDA Zone Info for Louisville

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 Louisville

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