One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. 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 International Falls can be read to estimate when it's a good idea to plant larkspur.

Planting Calendar for Larkspur

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

Larkspur do well in a bit of cold which tells us that you can plant them a lot earlier in the year than more sensitive plants.

The earliest that you can plant larkspur 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 larkspur and expect a good harvest is probably August. If you wait any later than that and your larkspur may not have a chance to grow to maturity. If you are starting your larkspur indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in International Falls. You can expect an average low temperature of -40°F in the coldest months of winter.

Remember that USDA zone info for International Falls is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in International Falls last frost occurs after May 15 be ready to cover your larkspur if you have a surprise 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.