Before planting it is a good idea to find your USDA Zone info to estimate 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.

You should be able to figure out when it's possible to plant nierembergia by referring to the USDA zone info for Forest Park.

Planting Calendar for Nierembergia

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

It's probably a bad idea to plant nierembergia until after the last frost because they require warm weather.

The earliest that you can plant nierembergia in Forest Park 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 nierembergia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your nierembergia may not have a chance to fully mature. You can get started a little bit earlier by starting your nierembergia indoors.

Last Frost Date

In Forest Park the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

Keep in mind that USDA zone info for Forest Park is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Forest Park there is a last frost after April 15 so make sure that you are prepared to cover your nierembergia in the event of one of those late frosts.

USDA Zone Info for Forest Park

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 Forest Park

You may be interested in your other planting guides for Forest Park.