One of the best tools that you have as gardeners to help us determine 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 first chance to plant phlox in Fairfax should be figured out by referring to 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.

Phlox tend to make it in moderate cold which means that you can plant them a little earlier in the year than other frost tender plants.

The earliest that you can plant phlox in Fairfax 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. If you wait any later than that and your phlox may not have a chance to grow to maturity. If you are starting your phlox indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in Fairfax. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Fairfax is just an average the actual date of last frost changes from year to year. Since half of the time in Fairfax it frosts late in the year after February 15 be ready to cover your phlox in the event of a late frost.

USDA Zone Info for Fairfax

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 Fairfax

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