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.

It's possible to estimate when it's the best time to plant primroses by using the USDA zone info for San Luis Obispo.

Planting Calendar for Primroses

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

Since primroses do well in cold you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant primroses 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 primroses and expect a good harvest is probably October. Any later than that and your primroses may not have a chance to grow to maturity. If you are starting your primroses indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in San Luis Obispo. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for San Luis Obispo is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in San Luis Obispo there is a last frost after February 15 so always be ready to cover your primroses in the event of 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.