The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Boulder City should be read to determine when it's possible to plant napa cabbage.

Planting Calendar for Napa cabbage

Frost tolerance for napa cabbage:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

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

The earliest that you can plant napa cabbage in Boulder 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 napa cabbage and expect a good harvest is probably October. If you wait any later than that and your napa cabbage may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your napa cabbage indoors.

Last Frost Date

On average all chance of frost has passed is on February 15 in Boulder City. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Boulder City may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Boulder City you get a frost after February 15 so make sure that you are prepared to cover your napa cabbage if you have a surprise late frost.

USDA Zone Info for Boulder 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 Boulder City

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