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.

By referring to the USDA zone info for Lathrop you should be able to estimate when it's the best time to plant primroses.

Planting Calendar for Primroses

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

Primroses can survive in cold weather which means that you can plant them earlier in the year than other plants that might not handle the cold.

The earliest that you can plant primroses in Lathrop 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. You probably don't want to wait any later than that or else your primroses may not have a chance to fully mature. Starting your primroses indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in Lathrop. You should expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Lathrop is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Lathrop you get a frost after February 15 be ready to cover your primroses if you have a surprise late frost.

USDA Zone Info for Lathrop

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 Lathrop

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