Before planting it is a good idea to find your USDA Zone info to figure out your garden 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 Iowa Falls should be reviewed to figure out when it's possible to plant thunbergia.

Planting Calendar for Thunbergia

Frost tolerance for thunbergia:	Not tolerant of frost.
When to plant:	After the last frost.

Since thunbergia do not do well in cold weather it is important to wait until after the last frost has passed before you can plant them.

The earliest that you can plant thunbergia in Iowa Falls 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 thunbergia and expect a good harvest is probably August. If you wait any later than that and your thunbergia may not have a chance to fully mature. If you are starting your thunbergia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Iowa Falls. You can expect an average low temperature of -20°F in the coldest months of winter.

Remember that USDA zone info for Iowa Falls is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Iowa Falls you get a frost after April 15 so make sure that you are prepared to cover your thunbergia if you have a late frost.

USDA Zone Info for Iowa Falls

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Iowa Falls

You may be interested in your other planting guides for Iowa Falls.