When to Plant Coleus in Portsmouth, NH

One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. 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 getting a good idea when it's possible to plant coleus is to examine the USDA zone info for Portsmouth.


Planting Calendar for Coleus

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

You really shouldn't plant coleus until after the last frost because they require warm weather.

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

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

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Portsmouth and it can change quite a bit from year to year. Half of the time in Portsmouth last frost occurs after April 15 so make sure that you are ready to protect your coleus if you have 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.