One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

The earliest that you can plant nierembergia in Onalaska can be figured out by referring to the USDA zone info.

Planting Calendar for Nierembergia

Frost tolerance for nierembergia:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

You should not plant nierembergia until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant nierembergia in Onalaska is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant nierembergia and expect a good harvest is probably August. If you wait any later than that and your nierembergia may not have a chance to grow to maturity. Starting your nierembergia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Onalaska the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -25°F.

Since the USDA zone info for Onalaska is just an average the actual date of last frost changes from year to year. Half of the time in Onalaska last frost occurs after May 15 so make sure that you are ready to cover your nierembergia if you have a surprise late frost.

USDA Zone Info for Onalaska

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 Onalaska

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