One of the best tools that you have as gardeners to help us figure out 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.

A way of getting a good idea when it's a good idea to plant primula is to check out the USDA zone info for Imperial.

Planting Calendar for Primula

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

Primula do well in a bit of cold which means that you can plant them earlier in the year than other frost tender plants.

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

The last month that you can plant primula and expect a good harvest is probably October. Any later than that and your primula may not have a chance to really do well. You can get started a few weeks earlier by starting your primula indoors.

Last Frost Date

In Imperial the average date of last frost happens on January 31. You should expect an average low temperature of 30°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 Imperial and it will vary from year to year. Since half of the time in Imperial last frost occurs after January 31 be ready to cover your primula in the event of one of those late frosts.

USDA Zone Info for Imperial

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Imperial

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