The USDA Zone info is a great tool for gardeners to help us estimate 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 determine when to plant tree onions by using the USDA zone info for Des Plaines.

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 slightly earlier in the year than more sensitive plants.

The earliest that you can plant tree onions in Des Plaines 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. Any later than that and your tree onions may not have a chance to really do well. You can get started a few weeks earlier by starting your tree onions indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Des Plaines. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Des Plaines may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Des Plaines you get a frost after April 15 be ready to protect your tree onions in the event of a late frost.

USDA Zone Info for Des Plaines

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 Des Plaines

You may be interested in your other planting guides for Des Plaines.