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.

A way of making a decision about when it's a good idea to plant napa cabbage is to use the USDA zone info for Diamond Bar.

Planting Calendar for Napa cabbage

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

Napa cabbage do well in cold weather which means that you can plant them quite a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant napa cabbage in Diamond Bar 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. Any later than that and your napa cabbage may not have a chance to fully mature. If you are starting your napa cabbage indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost is on January 31 in Diamond Bar. It might get as low as 30°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Diamond Bar and it is different every year. Half of the time in Diamond Bar you get surprised by a frost after January 31 so make sure that you are prepared to protect your napa cabbage in the event of a surprise late frost.

USDA Zone Info for Diamond Bar

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Diamond Bar

You may be interested in your other planting guides for Diamond Bar.