Before planting it is a good idea to find your USDA Zone info to determine 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.

You can figure out when it's a good idea to plant rhubarb in Portsmouth by checking out the USDA zone info.

Planting Calendar for Rhubarb

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

Rhubarb are one of those plants that can tolerate a little bit of cold weather which means that you can get them planted earlier than plants that are more sensitive to the cold.

The earliest that you can plant rhubarb 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 rhubarb and expect a good harvest is probably September. Any later than that and your rhubarb may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your rhubarb indoors.

Last Frost Date

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

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Portsmouth and it 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 protect your rhubarb 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.