The USDA Zone info is a great tool for gardeners to help us figure out your gardening 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 Zone 2b should be read to estimate when to plant tree onions.

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 do ok in very little cold which means that you can plant them just a tiny bit earlier in the year than more sensitive plants.

The earliest that you can plant tree onions in Zone 2b is May. However, you really should wait until June 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. You probably don't want to wait any later than that or else your tree onions may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your tree onions indoors.

Last Frost Date

The average date of last frost is May 15 in Zone 2b. In the coldest months of winter you should expect an average low temperature of -45°F.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Zone 2b and it changes from year to year. Since half of the time in Zone 2b you get a frost after May 15 be ready to protect your tree onions in the event of a surprise late frost.

USDA Zone Info for Zone 2b

Here is the info for USDA Zone 2b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	August 15
Lowest Expected Low	-45°F
Highest Expected Low	-40°F

This means that on a really cold year, the coldest it will get is -45°F. On most years you should be prepared to experience lows near -40°F.

Plants to Grow in Zone 2b

You may be interested in your other planting guides for Zone 2b.