Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to estimate when it's possible to plant bunching onions by checking out the USDA zone info for Zone 4b.

Planting Calendar for Bunching Onions

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

You can plant bunching onions a bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant bunching onions in Zone 4b 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 bunching onions and expect a good harvest is probably August. If you wait any later than that and your bunching onions may not have a chance to fully mature. You can get started a little bit earlier by starting your bunching onions indoors.

Last Frost Date

In Zone 4b the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -25°F.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Zone 4b and it is different every year. Since half of the time in Zone 4b you get a frost after May 15 be ready to protect your bunching onions in the event of a surprise late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.