The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Great Falls you can estimate when it's the best time to plant primroses by reviewing 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.

You can plant primroses much earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

The earliest that you can plant primroses in Great Falls is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant primroses and expect a good harvest is probably August. You probably don't want to wait any later than that or else your primroses may not have a chance to fully mature. If you are starting your primroses indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Great Falls the average date of last frost happens on May 15. You should expect an average low temperature of -30°F in the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Great Falls and it will vary from year to year. Half of the time in Great Falls you get surprised by a frost after May 15 so be sure to be ready to cover your primroses in the event of a surprise late frost.

USDA Zone Info for Great Falls

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Great Falls

You may be interested in your other planting guides for Great Falls.