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.

The USDA zone info for Great Falls should be reffered to in order to determine when you can plant lobelia.

Planting Calendar for Lobelia

Frost tolerance for lobelia:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant lobelia quite a bit 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 lobelia 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 lobelia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your lobelia may not have a chance to grow to maturity. If you are starting your lobelia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Great Falls the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Great Falls and it is different every year. Since half of the time in Great Falls you get surprised by a frost after May 15 be ready to protect your lobelia 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.