One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for San Ramon can be looked at to determine when it's a good idea to plant phlox.

Planting Calendar for Phlox

Frost tolerance for phlox:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since phlox do well in moderate cold you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant phlox in San Ramon 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 phlox and expect a good harvest is probably October. You probably don't want to wait any later than that or else your phlox may not have a chance to fully mature. Starting your phlox 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 San Ramon. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for San Ramon is an average the actual date of last frost is different every year. Half of the time in San Ramon you get a frost after February 15 so be sure to be ready to cover your phlox in the event of a late frost.

USDA Zone Info for San Ramon

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 Ramon

You may be interested in your other planting guides for San Ramon.