When to Plant Radishes in Portsmouth, NH

One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Portsmouth should be read to estimate when it's possible to plant radishes.


Planting Calendar for Radishes

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

Radishes are very cold tolerant which means that you can start planting them much earlier than other frost tender plants.

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

The earliest that you can plant radishes 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 radishes and expect a good harvest is probably September. You probably don't want to wait any later than that or else your radishes may not have a chance to fully mature. If you are starting your radishes indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Portsmouth. You should expect an average low temperature of -10°F in the coldest months of winter.

Keep in mind that USDA zone info for Portsmouth is just an average and the actual date of last frost will vary 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 radishes in the event of a surprise late frost.

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.