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

It's possible to determine when it's the best time to plant primula by checking out the USDA zone info for Stockton.

Planting Calendar for Primula

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

Primula tend to make it in pretty solid cold which tells us that you can plant them a lot earlier in the year than other plants that might not handle the cold.

The earliest that you can plant primula in Stockton 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. 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 few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Stockton. In the coldest months of winter you should expect an average low temperature of 25°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Stockton and it will vary from year to year. Since half of the time in Stockton you get a frost after February 15 be ready to protect your primula if you have a surprise late frost.

USDA Zone Info for Stockton

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Stockton

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