Before planting it is a good idea to find your USDA Zone info to determine 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 first opportunity to plant mimulus in Great Falls can be figured out by reviewing the USDA zone info.

Planting Calendar for Mimulus

Frost tolerance for mimulus:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since mimulus do not do well in cold weather you must wait until after all chance of frost has passed before you can plant them.

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

The last month that you can plant mimulus and expect a good harvest is probably August. If you wait any later than that and your mimulus may not have a chance to fully mature. Starting your mimulus indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on May 15 in Great Falls. It might get as low as -30°F during 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. Since half of the time in Great Falls you get surprised by a frost after May 15 be ready to protect your mimulus in the event of 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.