One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Granite City should be read to estimate when to plant ageratum.

Planting Calendar for Ageratum

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

You really shouldn't plant ageratum until after all chance of frost has passed because they require warm weather.

The earliest that you can plant ageratum in Granite City is April. However, you really should wait until May 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. If you are starting your ageratum indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Granite City. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Granite City is not always accurate the actual date of last frost changes from year to year. Since half of the time in Granite City you get a frost after April 15 be ready to protect your ageratum if you have a late frost.

USDA Zone Info for Granite City

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Granite City

You may be interested in your other planting guides for Granite City.