The USDA Zone info is a great tool for gardeners to help us determine 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 Portsmouth can be reffered to in order to figure out when it's a good idea to plant thyme.

Planting Calendar for Thyme

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

Since thyme do well in cold you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant thyme in Portsmouth 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 thyme and expect a good harvest is probably September. You probably don't want to wait any later than that or else your thyme may not have a chance to really do well. If you are starting your thyme indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Portsmouth. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Portsmouth is not always accurate the actual date of last frost changes from year to year. Half of the time in Portsmouth it frosts late in the year after April 15 so make sure that you are ready to cover your thyme in the event of a surprise late frost.

USDA Zone Info for Portsmouth

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Portsmouth

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