One of the first steps you take when you are estimating your gardening schedule is find your 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 a good idea to figure out when it's possible to plant primula by checking out the USDA zone info for Oroville.

Planting Calendar for Primula

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

Since primula do well in cold you can plant them a lot earlier in the year than more sensitive plants.

The earliest that you can plant primula in Oroville 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 fully mature. If you are starting your primula indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on February 15 in Oroville. You should expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Oroville is an average the actual date of last frost will vary from year to year. Half of the time in Oroville last frost occurs after February 15 so always be ready to protect your primula in the event of a surprise late frost.

USDA Zone Info for Oroville

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 Oroville

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