One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. 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 Chicago can be reviewed 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.

Napa cabbage do ok 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 Chicago 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 napa cabbage and expect a good harvest is probably September. If you wait any later than that and your napa cabbage may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your napa cabbage indoors.

Last Frost Date

The average date of last frost is April 15 in Chicago. In the coldest months of winter you can expect an average low temperature of -10°F.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Chicago and it can change quite a bit from year to year. Half of the time in Chicago you get a frost after April 15 so just be sure to be ready to protect your napa cabbage in the event of one of those late frosts.

USDA Zone Info for Chicago

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Chicago

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