One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's a good idea to determine when it's the best time to plant nierembergia by referring to the USDA zone info for Marengo.

Planting Calendar for Nierembergia

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

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

The earliest that you can plant nierembergia in Marengo 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 grow to maturity. Starting your nierembergia indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Marengo. In the coldest months of winter you can expect an average low temperature of -15°F.

Remember that USDA zone info for Marengo is not always accurate and the actual date of last frost is different every year. Half of the time in Marengo it frosts late in the year after April 15 so make sure that you are prepared to cover your nierembergia if you have one of those late frosts.

USDA Zone Info for Marengo

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 Marengo

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