Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Denison you will be able to figure out when it's the best time 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.

Since nigella are one of those plants that can tolerate quite a bit of cold weather you can plant them earlier in the year than other plants that might not handle the cold.

The earliest that you can plant nigella in Denison 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 grow to maturity. You can get started a few weeks earlier by starting your nigella indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Denison. You should expect an average low temperature of -20°F in the coldest months of winter.

Remember that USDA zone info for Denison is just an average and the actual date of last frost will vary from year to year. Half of the time in Denison last frost occurs after April 15 so just be sure to be ready to cover your nigella if you have a surprise late frost.

USDA Zone Info for Denison

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Denison

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