One of the first steps you take when you are getting a good idea 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.

In Berkley you can determine when it's a good idea to plant tree onions by checking out the USDA zone info.

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.

You can plant tree onions slightly earlier in the year because they are barely cold tolerant.

The earliest that you can plant tree onions in Berkley 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 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 few weeks earlier by starting your tree onions indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Berkley. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Berkley is an average the actual date of last frost is different every year. Half of the time in Berkley you get surprised by a frost after April 15 so be sure to be ready to cover your tree onions in the event of one of those late frosts.

USDA Zone Info for Berkley

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Berkley

You may be interested in your other planting guides for Berkley.