The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In South Portland you can estimate when it's possible to plant primroses by looking at the USDA zone info.

Planting Calendar for Primroses

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

Primroses do ok in cold weather which tells us that you can plant them earlier in the year than more sensitive plants.

The earliest that you can plant primroses 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 primroses and expect a good harvest is probably September. If you wait any later than that and your primroses may not have a chance to fully mature. Starting your primroses 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 South Portland. In the coldest months of winter you can expect an average low temperature of -15°F.

It's important to remember that USDA zone info for South Portland is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in South Portland there is a last frost after April 15 be ready to cover your primroses 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.