The USDA Zone info is a great tool for gardeners to help us estimate 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.

By looking at the USDA zone info for Portsmouth it's a good idea to determine when it's the best time to plant nasturtium.

Planting Calendar for Nasturtium

Frost tolerance for nasturtium:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's not a good idea to plant nasturtium until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant nasturtium in Portsmouth is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant nasturtium and expect a good harvest is probably August. Any later than that and your nasturtium may not have a chance to really do well. You can get started a few weeks earlier by starting your nasturtium indoors.

Last Frost Date

On average the last frost is on April 15 in Portsmouth. It might get as low as -5°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Portsmouth and it changes from year to year. Half of the time in Portsmouth there is a last frost after April 15 so always be ready to cover your nasturtium if you have 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.