Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Great Falls can be used to estimate when to plant scallions.

Planting Calendar for Scallions

Frost tolerance for scallions:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Scallions do well in a tiny bit of cold which tells us that you can plant them a bit earlier in the year than other frost tender plants.

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

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.

Just be sure to remember that USDA zone info for Great Falls is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Great Falls you get surprised by a frost after May 15 so make sure that you are ready to cover your scallions if you have a 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.