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.

A way of estimating when to plant tree onions is to use the USDA zone info for Wooster.

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 plants that might not handle the cold.

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

Last Frost Date

In Wooster the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Since the USDA zone info for Wooster is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Wooster you get a frost after April 15 so make sure that you are prepared to cover your tree onions in the event of one of those late frosts.

USDA Zone Info for Wooster

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 Wooster

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