The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's possible to figure out when you can plant geranium by checking out the USDA zone info for Alton.

Planting Calendar for Geranium

Frost tolerance for geranium:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since geranium do not do well in cold weather it is necessary to wait until after the last frost before you can plant them.

The earliest that you can plant geranium in Alton 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 geranium and expect a good harvest is probably August. Any later than that and your geranium may not have a chance to grow to maturity. If you are starting your geranium indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Alton. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Alton is just an average the actual date of last frost will vary from year to year. Since half of the time in Alton last frost occurs after April 15 be ready to cover your geranium if you have one of those late frosts.

USDA Zone Info for Alton

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Alton

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