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.

It's possible to estimate when to plant tree onions by using the USDA zone info for Jefferson.

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 tells us that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant tree onions in Jefferson 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. You can get started a little bit earlier by starting your tree onions indoors.

Last Frost Date

On average all chance of frost has passed is on March 15 in Jefferson. You can expect an average low temperature of 10°F in the coldest months of winter.

Remember that USDA zone info for Jefferson is an average and the actual date of last frost changes from year to year. Half of the time in Jefferson it frosts late in the year after March 15 so just be sure to be ready to protect your tree onions in the event of a surprise late frost.

USDA Zone Info for Jefferson

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Jefferson

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