The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In San Luis Obispo you can estimate when to plant primula 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.

Primula do ok in cold weather which tells us that you can plant them earlier in the year than other plants that might not handle the cold.

The earliest that you can plant primula in San Luis Obispo 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 fully mature. Starting your primula indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in San Luis Obispo. In the coldest months of winter you should expect an average low temperature of 25°F.

Just be sure to remember that USDA zone info for San Luis Obispo is not always accurate and the actual date of last frost changes from year to year. Since half of the time in San Luis Obispo it frosts late in the year after February 15 be ready to cover your primula if you have a late frost.

USDA Zone Info for San Luis Obispo

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 San Luis Obispo

You may be interested in your other planting guides for San Luis Obispo.