One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of determining when it's the best time to plant iceberg lettuce is to refer to the USDA zone info for Decorah.

Planting Calendar for Iceberg lettuce

Frost tolerance for iceberg lettuce:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since iceberg lettuce do ok in moderate cold you can plant them just a tiny bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant iceberg lettuce in Decorah 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 iceberg lettuce and expect a good harvest is probably August. Any later than that and your iceberg lettuce may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your iceberg lettuce indoors.

Last Frost Date

The average date of last frost is May 15 in Decorah. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Decorah may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Decorah you get surprised by a frost after May 15 be ready to protect your iceberg lettuce in the event of a late frost.

USDA Zone Info for Decorah

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Decorah

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