Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant primroses in Cupertino can be figured out by checking out the USDA zone info.

Planting Calendar for Primroses

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

Primroses tend to make it in pretty solid cold which means that you can plant them much earlier in the year than other frost tender plants.

The earliest that you can plant primroses in Cupertino 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 fully mature. If you are starting your primroses indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Cupertino the average date of last frost happens on February 15. You should expect an average low temperature of 25°F in the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Cupertino and it can change quite a bit from year to year. Since half of the time in Cupertino last frost occurs after February 15 be ready to protect your primroses in the event of a late frost.

USDA Zone Info for Cupertino

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 Cupertino

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