One of the first steps you take when you are figuring out 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.

In Onalaska you can determine when it's possible to plant ageratum by checking out the USDA zone info.

Planting Calendar for Ageratum

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

You can not plant ageratum until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant ageratum 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 ageratum and expect a good harvest is probably August. Any later than that and your ageratum may not have a chance to really do well. Starting your ageratum 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 can expect an average low temperature of -25°F.

It's important to remember that USDA zone info for Onalaska is an average and the actual date of last frost changes from year to year. Half of the time in Onalaska there is a last frost after May 15 so just be sure to be ready to protect your ageratum if you have one of those late frosts.

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.