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.

The USDA zone info for Great Falls should be used to estimate when to plant geranium.

Planting Calendar for Geranium

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

Geranium are not cold tolerant which means that you really should wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant geranium 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 geranium and expect a good harvest is probably August. Any later than that and your geranium may not have a chance to grow to maturity. You can get started a little bit earlier by starting your geranium indoors.

Last Frost Date

On average all chance of frost has passed is on May 15 in Great Falls. It might get as low as -30°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Great Falls and it 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 always be ready to cover your geranium if you have 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.