One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of making a decision about when it's a good idea to plant nigella is to look at the USDA zone info for Rock Springs.

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 very cold tolerant you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant nigella in Rock Springs 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. Starting your nigella indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Rock Springs the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -20°F.

Since the USDA zone info for Rock Springs is not always accurate the actual date of last frost changes from year to year. Since half of the time in Rock Springs you get a frost after April 15 be ready to protect your nigella if you have a late frost.

USDA Zone Info for Rock Springs

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 Rock Springs

You may be interested in your other planting guides for Rock Springs.