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 can estimate when it's possible to plant campanula in Alton by looking at the USDA zone info.

Planting Calendar for Campanula

Frost tolerance for campanula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant campanula just a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant campanula in Alton is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant campanula and expect a good harvest is probably September. You probably don't want to wait any later than that or else your campanula may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your campanula 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 changes from year to year. Since half of the time in Alton you get surprised by a frost after April 15 be ready to protect your campanula in the event of a surprise 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.