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.

By referring to the USDA zone info for Williamsport you should be able to determine when it's possible to plant nierembergia.

Planting Calendar for Nierembergia

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

Since nierembergia do not do well in cold weather it's necessary to wait until after the last frost before you can plant them.

The earliest that you can plant nierembergia in Williamsport 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. 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

On average the last frost is on April 15 in Williamsport. In the coldest months of winter you should expect an average low temperature of -5°F.

Keep in mind that USDA zone info for Williamsport is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Williamsport it frosts late in the year after April 15 so make sure that you are ready to protect your nierembergia in the event of one of those late frosts.

USDA Zone Info for Williamsport

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 Williamsport

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