One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By reviewing the USDA zone info for Slinger it's possible to determine when it's a good idea to plant tree onions.

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 do ok in moderate cold you can plant them a bit earlier in the year than more sensitive plants.

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

Last Frost Date

The average date of last frost is April 15 in Slinger. In the coldest months of winter you should expect an average low temperature of -20°F.

It's important to remember that USDA zone info for Slinger is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Slinger you get surprised by a frost after April 15 so make sure that you are ready to protect your tree onions in the event of a surprise late frost.

USDA Zone Info for Slinger

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Slinger

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