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

In Napa you can figure out when you can plant phlox by using the USDA zone info.

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 a little bit earlier in the year than other frost tender plants.

The earliest that you can plant phlox in Napa 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. Any later than that and your phlox may not have a chance to really do well. If you are starting your phlox indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in Napa. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Napa 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 Napa you get surprised by a frost after February 15 be ready to protect your phlox in the event of a surprise late frost.

USDA Zone Info for Napa

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 Napa

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