One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. 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 reffered to in order to estimate when you can plant nigella.

Planting Calendar for Nigella

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

You can plant nigella a lot earlier in the year because they do well in cold.

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

Last Frost Date

On average all chance of frost has passed is on May 15 in Great Falls. 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. Half of the time in Great Falls there is a last frost after May 15 so be sure to be ready to cover your nigella in the event of one of those late frosts.

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.