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.

The USDA zone info for Alton can be reviewed to estimate when you can plant iberis.

Planting Calendar for Iberis

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

Iberis are one of those plants that can tolerate a little bit of cold weather which tells us that you can get them planted earlier than other plants that might not handle the cold.

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

Last Frost Date

On average all chance of frost has passed is on April 15 in Alton. It might get as low as -10°F during the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Alton and it will vary from year to year. Half of the time in Alton last frost occurs after April 15 so be sure to be ready to cover your iberis 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.