The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. 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 tree onions by reviewing the USDA zone info for Devils Lake.

Planting Calendar for Tree onions

Frost tolerance for tree onions:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Tree onions are barely cold tolerant which means that you can get them planted just a bit earlier than other plants that might not handle the cold.

The earliest that you can plant tree onions in Devils Lake is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant tree onions and expect a good harvest is probably August. If you wait any later than that and your tree onions may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your tree onions indoors.

Last Frost Date

On average all chance of frost has passed is on May 15 in Devils Lake. You can expect an average low temperature of -30°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Devils Lake is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Devils Lake there is a last frost after May 15 so be sure to be ready to protect your tree onions if you have one of those late frosts.

USDA Zone Info for Devils Lake

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 Devils Lake

You may be interested in your other planting guides for Devils Lake.