One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant nigella in Iowa City can be figured out by referring to 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 do well in cold which tells us that you can get them planted much earlier than plants that are more sensitive to the cold.

The earliest that you can plant nigella in Iowa City 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 really do well. You can get started a little bit earlier by starting your nigella indoors.

Last Frost Date

In Iowa City the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that USDA zone info for Iowa City is an average and the actual date of last frost changes from year to year. Since half of the time in Iowa City you get a frost after April 15 be ready to protect your nigella if you have a surprise late frost.

USDA Zone Info for Iowa City

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 Iowa City

You may be interested in your other planting guides for Iowa City.