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.

By checking out the USDA zone info for Helena it's a good idea to estimate when to plant geranium.

Planting Calendar for Geranium

Frost tolerance for geranium:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's probably not a good idea to plant geranium until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant geranium in Helena 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 fully mature. If you are starting your geranium indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Helena. It might get as low as -25°F during the coldest months of winter.

Always keep in mind 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 Helena and it is different every year. Half of the time in Helena it frosts late in the year after May 15 so be sure to be ready to cover your geranium in the event of a surprise late frost.

USDA Zone Info for Helena

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Helena

You may be interested in your other planting guides for Helena.