One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to determine when it's possible to plant nigella by looking at the USDA zone info for International Falls.

Planting Calendar for Nigella

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

Since nigella are very cold tolerant you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant nigella in International 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. If you wait any later than that and your nigella may not have a chance to really do well. Starting your nigella indoors is a great way to get them started a little bit earlier.

Last Frost Date

In International Falls the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -40°F.

Since the USDA zone info for International Falls is just an average the actual date of last frost is different every year. Since half of the time in International Falls you get a frost after May 15 be ready to cover your nigella in the event of a late frost.

USDA Zone Info for International Falls

Here is the info for USDA Zone 3a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-40°F
Highest Expected Low	-35°F

This means that on a really cold year, the coldest it will get is -40°F. On most years you should be prepared to experience lows near -35°F.

Plants to Grow in International Falls

You may be interested in your other planting guides for International Falls.