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.

A way of determining when you can plant onions is to look at the USDA zone info for Eau Claire.

Planting Calendar for Onions

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

Onions are very cold tolerant which tells us that you can get them planted much earlier than other frost tender plants.

The earliest that you can plant onions in Eau Claire 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 onions and expect a good harvest is probably August. Any later than that and your onions may not have a chance to fully mature. If you are starting your onions indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Eau Claire. It might get as low as -25°F during the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Eau Claire and it changes from year to year. Half of the time in Eau Claire last frost occurs after May 15 so make sure that you are ready to protect your onions if you have a surprise late frost.

USDA Zone Info for Eau Claire

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Eau Claire

You may be interested in your other planting guides for Eau Claire.