One of the best tools that you have as gardeners to help us determine 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.

You should be able to estimate when it's the best time to plant nierembergia by checking out the USDA zone info for Pittsburgh.

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 has passed because they do not do well in cold weather.

The earliest that you can plant nierembergia in Pittsburgh 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 few weeks earlier.

Last Frost Date

In Pittsburgh the average date of last frost happens on April 15. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Pittsburgh may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Pittsburgh last frost occurs after April 15 so be sure to be ready to cover your nierembergia in the event of a surprise late frost.

USDA Zone Info for Pittsburgh

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Pittsburgh

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