The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Harrisburg you can estimate when it's a good idea to plant nigella by looking at the USDA zone info.

Planting Calendar for Nigella

Frost tolerance for nigella:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Nigella are one of those plants that can tolerate quite a bit of cold weather which means that you can plant them much earlier than other plants that might not handle the cold.

The earliest that you can plant nigella in Harrisburg is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant nigella and expect a good harvest is probably September. Any later than that and your nigella may not have a chance to really do well. You can get started a couple of weeks earlier by starting your nigella indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Harrisburg. You should expect an average low temperature of 5°F in the coldest months of winter.

Since the USDA zone info for Harrisburg may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Harrisburg it frosts late in the year after April 15 so always be ready to protect your nigella if you have one of those late frosts.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°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 10°F.

Plants to Grow in Harrisburg

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