One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's possible to estimate when you can plant zinnia by checking out the USDA zone info for Iowa Falls.

Planting Calendar for Zinnia

Frost tolerance for zinnia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Zinnia do not do well in cold weather which tells us that you must wait until it warms up after the last frost before you can plant them.

The earliest that you can plant zinnia 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 zinnia and expect a good harvest is probably August. If you wait any later than that and your zinnia may not have a chance to fully mature. You can get started a little bit earlier by starting your zinnia indoors.

Last Frost Date

The average date of last frost is April 15 in Iowa Falls. It might get as low as -20°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Iowa Falls and it is different every year. Since half of the time in Iowa Falls there is a last frost after April 15 be ready to cover your zinnia in the event of a surprise 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.