Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Alton you can determine when you can plant canna by referring to the USDA zone info.

Planting Calendar for Canna

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

You can not plant canna until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant canna 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 canna and expect a good harvest is probably August. Any later than that and your canna may not have a chance to fully mature. If you are starting your canna indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Alton the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Alton and it is different every year. Half of the time in Alton you get surprised by a frost after April 15 so just be sure to be ready to protect your canna in the event of 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.