Before planting it is a good idea to find your USDA Zone info to figure out your garden 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 Iowa Falls can be used to determine when you can plant calendula.

Planting Calendar for Calendula

Frost tolerance for calendula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Calendula can survive in mild cold which means that you can plant them a little earlier in the year than other frost tender plants.

The earliest that you can plant calendula in Iowa Falls is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant calendula and expect a good harvest is probably September. You probably don't want to wait any later than that or else your calendula may not have a chance to really do well. You can get started a couple of weeks earlier by starting your calendula indoors.

Last Frost Date

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

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Iowa Falls and it changes from year to year. Since half of the time in Iowa Falls it frosts late in the year after April 15 be ready to protect your calendula 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.