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

The first opportunity to plant nigella in Rio Grande City should be figured out by reviewing 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.

Since nigella are very cold tolerant you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant nigella in Rio Grande City is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant nigella and expect a good harvest is probably October. Any later than that and your nigella may not have a chance to grow to maturity. You can get started a little bit earlier by starting your nigella indoors.

Last Frost Date

In Rio Grande City the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Rio Grande City is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Rio Grande City you get surprised by a frost after February 15 be ready to cover your nigella if you have a late frost.

USDA Zone Info for Rio Grande City

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Rio Grande City

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