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

A way of making a decision about when it's a good idea to plant nierembergia is to consult the USDA zone info for Gretna.

Planting Calendar for Nierembergia

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

It's not a good idea to plant nierembergia until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant nierembergia in Gretna 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. Any later than that and your nierembergia may not have a chance to grow to maturity. Starting your nierembergia 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 Gretna. You can expect an average low temperature of -15°F in the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Gretna and it will vary from year to year. Half of the time in Gretna you get surprised by a frost after April 15 so just be sure to be ready to protect your nierembergia if you have one of those late frosts.

USDA Zone Info for Gretna

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Gretna

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