The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of determining when it's possible to plant nigella is to check out the USDA zone info for Swarthmore.

Planting Calendar for Nigella

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

You can plant nigella a lot earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

The earliest that you can plant nigella in Swarthmore 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 few weeks earlier.

Last Frost Date

In Swarthmore the average date of last frost happens on April 15. You can expect an average low temperature of 0°F in the coldest months of winter.

Since the USDA zone info for Swarthmore is an average the actual date of last frost is different every year. Since half of the time in Swarthmore last frost occurs after April 15 be ready to cover your nigella if you have one of those late frosts.

USDA Zone Info for Swarthmore

Here is the info for USDA Zone 7a.

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

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

Plants to Grow in Swarthmore

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