The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. 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 Mount Vernon can be read to figure out when it's the best time 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.

Since tree onions are barely cold tolerant you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant tree onions in Mount Vernon 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. If you wait any later than that and your tree onions may not have a chance to really do well. If you are starting your tree onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Mount Vernon. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Mount Vernon may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Mount Vernon you get a frost after April 15 so be sure to be ready to cover your tree onions in the event of a surprise late frost.

USDA Zone Info for Mount Vernon

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Mount Vernon

You may be interested in your other planting guides for Mount Vernon.