Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Clayton you should be able to estimate when you can plant primula.

Planting Calendar for Primula

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

Primula are one of those plants that can tolerate quite a bit of cold weather which means that you can start planting them much earlier than plants that are more sensitive to the cold.

The earliest that you can plant primula in Clayton 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. Any later than that and your primula may not have a chance to really do well. Starting your primula indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Clayton. You can expect an average low temperature of 5°F in the coldest months of winter.

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 Clayton and it will vary from year to year. Half of the time in Clayton you get a frost after April 15 so always be ready to cover your primula in the event of a late frost.

USDA Zone Info for Clayton

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Clayton

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