The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Decorah should be reviewed to figure out when to plant sunflowers.

Planting Calendar for Sunflowers

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

Since sunflowers do not do well in cold weather you have to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant sunflowers 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 sunflowers and expect a good harvest is probably August. Any later than that and your sunflowers may not have a chance to fully mature. Starting your sunflowers indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Decorah. In the coldest months of winter you should expect an average low temperature of -25°F.

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. Half of the time in Decorah you get surprised by a frost after May 15 so make sure that you are ready to cover your sunflowers 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.