One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to estimate when you can plant schizanthus by checking out the USDA zone info for Alton.

Planting Calendar for Schizanthus

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

You really shouldn't plant schizanthus until after the last frost because they are not cold tolerant.

The earliest that you can plant schizanthus 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 schizanthus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your schizanthus may not have a chance to fully mature. You can get started a little bit earlier by starting your schizanthus indoors.

Last Frost Date

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

Since the USDA zone info for Alton is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Alton you get a frost after April 15 be ready to protect your schizanthus if you have a late frost.

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.