Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant alternaria in Decorah should be figured out by referring to the USDA zone info.

Planting Calendar for Alternaria

Frost tolerance for alternaria:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Alternaria are not cold tolerant which means that it's necessary to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant alternaria in Decorah is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant alternaria and expect a good harvest is probably August. You probably don't want to wait any later than that or else your alternaria may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your alternaria indoors.

Last Frost Date

In Decorah the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Decorah and it changes from year to year. Half of the time in Decorah last frost occurs after May 15 so be sure to be ready to cover your alternaria in the event of one of those late frosts.

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.