Before planting it is a good idea to find your USDA Zone info to figure out 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.

You should be able to estimate when you can plant primula by looking at the USDA zone info for Rancho Cucamonga.

Planting Calendar for Primula

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

Since primula are one of those plants that can tolerate quite a bit of cold weather you can plant them earlier in the year than more sensitive plants.

The earliest that you can plant primula in Rancho Cucamonga 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. You probably don't want to wait any later than that or else your primula may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your primula indoors.

Last Frost Date

On average all chance of frost has passed is on February 15 in Rancho Cucamonga. 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 Rancho Cucamonga may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Rancho Cucamonga you get surprised by a frost after February 15 be ready to protect your primula if you have one of those late frosts.

USDA Zone Info for Rancho Cucamonga

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 Rancho Cucamonga

You may be interested in your other planting guides for Rancho Cucamonga.