The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. 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 Decorah can be looked at to estimate when it's the best time to plant lobelia.

Planting Calendar for Lobelia

Frost tolerance for lobelia:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Lobelia can survive in quite a bit of cold which means that you can plant them quite a bit earlier in the year than other frost tender plants.

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

The last month that you can plant lobelia and expect a good harvest is probably August. If you wait any later than that and your lobelia may not have a chance to fully mature. If you are starting your lobelia indoors then you might be able to get away with starting them 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 can expect an average low temperature of -25°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Decorah and it will vary from year to year. Half of the time in Decorah last frost occurs after May 15 so just be sure to be ready to protect your lobelia 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.