The USDA Zone info is a great tool for gardeners to help us estimate 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.

A way of estimating when to plant zinnia is to refer to the USDA zone info for Indianapolis.

Planting Calendar for Zinnia

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

It's a bad idea to plant zinnia until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant zinnia in Indianapolis 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. You probably don't want to wait any later than that or else your zinnia may not have a chance to really do well. Starting your zinnia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Indianapolis. You should expect an average low temperature of -10°F in the coldest months of winter.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Indianapolis and it can change quite a bit from year to year. Half of the time in Indianapolis it frosts late in the year after April 15 so just be sure to be ready to cover your zinnia in the event of a surprise late frost.

USDA Zone Info for Indianapolis

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Indianapolis

You may be interested in your other planting guides for Indianapolis.