One of the best tools that you have as gardeners to help us figure out 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 USDA zone info for South Portland can be reffered to in order to determine when to plant spearmint.

Planting Calendar for Spearmint

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

Spearmint do well in cold which means that you can get them planted much earlier than more sensitive plants.

The earliest that you can plant spearmint in South Portland 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 spearmint and expect a good harvest is probably September. If you wait any later than that and your spearmint may not have a chance to fully mature. Starting your spearmint indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in South Portland. It might get as low as -15°F during the coldest months of winter.

Keep in mind that USDA zone info for South Portland may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in South Portland you get surprised by a frost after April 15 so always be ready to cover your spearmint in the event of one of those late frosts.

USDA Zone Info for South Portland

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 South Portland

You may be interested in your other planting guides for South Portland.