One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to determine when it's possible to plant tree onions by using the USDA zone info for Hillsdale.

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 plants that might not handle the cold.

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

Last Frost Date

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

Remember that USDA zone info for Hillsdale is just an average and the actual date of last frost changes from year to year. Since half of the time in Hillsdale you get a frost after April 15 be ready to protect your tree onions if you have one of those late frosts.

USDA Zone Info for Hillsdale

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Hillsdale

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