Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant nierembergia in Riverdale should be determined by looking at the USDA zone info.

Planting Calendar for Nierembergia

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

Nierembergia are not cold tolerant which means that you really should wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant nierembergia in Riverdale 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 really do well. If you are starting your nierembergia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Riverdale. It might get as low as -10°F during the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Riverdale and it changes from year to year. Since half of the time in Riverdale last frost occurs after April 15 be ready to cover your nierembergia if you have one of those late frosts.

USDA Zone Info for Riverdale

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 Riverdale

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