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

By using the USDA zone info for Cary it's possible to estimate when it's possible to plant nigella.

Planting Calendar for Nigella

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

Nigella do well in cold which tells us that you can start planting them much earlier than other frost tender plants.

The earliest that you can plant nigella in Cary 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. If you wait any later than that and your nigella may not have a chance to grow to maturity. If you are starting your nigella indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Cary. You can expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Cary is an average the actual date of last frost is different every year. Half of the time in Cary you get surprised by a frost after April 15 so make sure that you are ready to cover your nigella if you have one of those late frosts.

USDA Zone Info for Cary

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 Cary

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