When to Plant Onions in Somersworth, NH

One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant onions in Somersworth can be determined by looking at the USDA zone info.


Planting Calendar for Onions

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

Onions are one of those plants that can tolerate quite a bit of cold weather which means that you can start planting them much earlier than more sensitive plants.

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

The earliest that you can plant onions in Somersworth 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 onions and expect a good harvest is probably September. If you wait any later than that and your onions may not have a chance to really do well. Starting your onions indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Somersworth. In the coldest months of winter you should expect an average low temperature of -15°F.

It's important to remember that USDA zone info for Somersworth is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Somersworth it frosts late in the year after April 15 so just be sure to be ready to cover your onions if you have a surprise late frost.

USDA Zone Info for Somersworth

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Somersworth

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