Before planting it is a good idea to find your USDA Zone info to determine 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.

It's a good idea to determine when you can plant tree onions by referring to the USDA zone info for Union.

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 do well in very little cold which tells us that you can plant them just a tiny bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant tree onions in Union 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. Starting your tree onions indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Union and it will vary from year to year. Half of the time in Union last frost occurs after April 15 so be sure to be ready to protect your tree onions in the event of a late frost.

USDA Zone Info for Union

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 Union

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