Before planting it is a good idea to find your USDA Zone info to figure out your garden 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 can be read to estimate when it's possible to plant calendula.

Planting Calendar for Calendula

Frost tolerance for calendula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Calendula do ok in moderate cold which tells us that you can plant them a little bit earlier in the year than more sensitive plants.

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

Last Frost Date

In Great Falls the average date of last frost happens on May 15. You can expect an average low temperature of -30°F in the coldest months of winter.

Remember that USDA zone info for Great Falls is an average and the actual date of last frost changes from year to year. Since half of the time in Great Falls last frost occurs after May 15 be ready to protect your calendula 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.