Before planting it is a good idea to find your USDA Zone info to figure out 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 estimate when it's possible to plant onions by reviewing the USDA zone info for Mukwonago.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant onions earlier in the year because they do well in cold.

The earliest that you can plant onions in Mukwonago is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant onions and expect a good harvest is probably September. Any later than that and your onions may not have a chance to grow to maturity. If you are starting your onions indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Mukwonago may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Mukwonago you get surprised by a frost after April 15 so just be sure to be ready to cover your onions if you have a surprise late frost.

USDA Zone Info for Mukwonago

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 Mukwonago

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