One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

By referring to the USDA zone info for Portsmouth it's possible to estimate when it's the best time to plant leeks.

Planting Calendar for Leeks

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

Leeks 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 other frost tender plants.

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

Last Frost Date

The average date of last frost is April 15 in Portsmouth. It might get as low as -10°F during the coldest months of winter.

Always keep in mind that USDA zone info for Portsmouth may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Since half of the time in Portsmouth you get a frost after April 15 be ready to cover your leeks in the event of a 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.