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.

You can figure out when it's possible to plant iberis in Portsmouth by looking at the USDA zone info.

Planting Calendar for Iberis

Frost tolerance for iberis:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant iberis just a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant iberis 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 iberis and expect a good harvest is probably September. Any later than that and your iberis may not have a chance to fully mature. If you are starting your iberis indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Portsmouth the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Remember that USDA zone info for Portsmouth is an average and the actual date of last frost changes from year to year. Half of the time in Portsmouth you get a frost after April 15 so be sure to be ready to cover your iberis in the event of one of those late frosts.

USDA Zone Info for Portsmouth

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Portsmouth

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