One of the best tools that you have as gardeners to help us determine 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.

You should be able to estimate when it's possible to plant ageratum by using the USDA zone info for Belle Plaine.

Planting Calendar for Ageratum

Frost tolerance for ageratum:	Not tolerant of frost.
When to plant:	After the last frost.

Ageratum are not cold tolerant which tells us that it's necessary to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant ageratum in Belle Plaine 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. If you wait any later than that and your ageratum may not have a chance to really do well. If you are starting your ageratum indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Since the USDA zone info for Belle Plaine is not always accurate the actual date of last frost changes from year to year. Since half of the time in Belle Plaine it frosts late in the year after May 15 be ready to protect your ageratum if you have a surprise late frost.

USDA Zone Info for Belle Plaine

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 Belle Plaine

You may be interested in your other planting guides for Belle Plaine.