The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Somersworth should be read 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 are one of those plants that can tolerate a little bit of cold weather you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant phlox in Somersworth is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant phlox and expect a good harvest is probably September. Any later than that and your phlox may not have a chance to grow to maturity. 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 April 15 in Somersworth. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Somersworth is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Somersworth it frosts late in the year after April 15 be ready to protect your phlox if you have a late frost.

USDA Zone Info for Somersworth

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Somersworth

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