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 USDA zone info for South Portland can be reffered to in order to determine when it's the best time to plant impatiens.

Planting Calendar for Impatiens

Frost tolerance for impatiens:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's not a good idea to plant impatiens until after the last frost because they do not do well in cold weather.

The earliest that you can plant impatiens in South Portland is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant impatiens and expect a good harvest is probably August. Any later than that and your impatiens may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your impatiens indoors.

Last Frost Date

The average date of last frost is April 15 in South Portland. You should expect an average low temperature of -15°F in the coldest months of winter.

Just be sure to remember that USDA zone info for South Portland is not always accurate and the actual date of last frost is different every year. Since half of the time in South Portland you get surprised by a frost after April 15 be ready to protect your impatiens if you have a surprise late frost.

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.