The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant tritoma in Portsmouth should be figured out by referring to the USDA zone info.

Planting Calendar for Tritoma

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

You can plant tritoma a lot earlier in the year because they do well in cold.

The earliest that you can plant tritoma 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 tritoma and expect a good harvest is probably September. If you wait any later than that and your tritoma may not have a chance to really do well. You can get started a few weeks earlier by starting your tritoma indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Portsmouth. You should expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Portsmouth may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Portsmouth you get a frost after April 15 be ready to cover your tritoma in the event of one of those late frosts.

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.