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.

It's possible to estimate when it's a good idea to plant nigella by checking out the USDA zone info for Harvard.

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 pretty solid cold which means that you can plant them much earlier in the year than other frost tender plants.

The earliest that you can plant nigella in Harvard 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 fully mature. You can get started a little bit earlier by starting your nigella indoors.

Last Frost Date

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

Keep in mind that USDA zone info for Harvard may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in Harvard you get surprised by a frost after April 15 be ready to protect your nigella in the event of a late frost.

USDA Zone Info for Harvard

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 Harvard

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