When to Plant Pentas in Portsmouth, NH

Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of figuring out when it's the best time to plant pentas is to use the USDA zone info for Portsmouth.


Planting Calendar for Pentas

Frost tolerance for pentas: Not tolerant of frost.
When to plant: After the last frost when the weather gets warmer.

Pentas do not do well in cold weather which means that you really should wait until it warms up after the last frost before you can plant them.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant pentas
Possibly ok, but a risky time to plant pentas
Probably not a good time to plant pentas

The earliest that you can plant pentas 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 pentas and expect a good harvest is probably August. Any later than that and your pentas may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your pentas indoors.

Last Frost Date

In Portsmouth the average date of last frost happens on April 15. You can expect an average low temperature of -10°F in 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 will vary from year to year. Since half of the time in Portsmouth you get a frost after April 15 be ready to protect your pentas 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.