One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of determining when to plant nierembergia is to check out the USDA zone info for Rome.

Planting Calendar for Nierembergia

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

Nierembergia are not cold tolerant which tells us that you have to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant nierembergia in Rome 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. If you wait any later than that and your nierembergia may not have a chance to fully mature. 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

In Rome the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -20°F.

Always keep in mind that USDA zone info for Rome may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Rome there is a last frost after April 15 so make sure that you are prepared to cover your nierembergia in the event of a surprise late frost.

USDA Zone Info for Rome

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 Rome

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