When to Plant Sweet Williams 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 best time to plant sweet williams in Portsmouth should be estimated by looking at the USDA zone info.


Planting Calendar for Sweet Williams

Frost tolerance for sweet williams: Tolerant of some frost.
When to plant: Up to 5 weeks before last frost.

Since sweet williams do well in moderate cold you can plant them a bit earlier in the year than other plants that might not handle the cold.

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

The earliest that you can plant sweet williams 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 sweet williams and expect a good harvest is probably September. You probably don't want to wait any later than that or else your sweet williams may not have a chance to grow to maturity. Starting your sweet williams indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Portsmouth. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Portsmouth may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Portsmouth last frost occurs after April 15 be ready to cover your sweet williams 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.