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

One way of estimating when to plant tree onions is to use the USDA zone info for Willow Springs.

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.

You can plant tree onions slightly earlier in the year because they are barely cold tolerant.

The earliest that you can plant tree onions in Willow Springs 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. Starting your tree onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Willow Springs. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Willow Springs is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Willow Springs you get a frost after April 15 be ready to cover your tree onions in the event of a late frost.

USDA Zone Info for Willow Springs

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 Willow Springs

You may be interested in your other planting guides for Willow Springs.