One of the first steps you take when you are getting a good idea 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.

A way of determining when it's a good idea to plant bok choi is to look at the USDA zone info for Hillsboro.

Planting Calendar for Bok Choi

Frost tolerance for bok choi:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant bok choi just a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant bok choi in Hillsboro 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 bok choi and expect a good harvest is probably September. Any later than that and your bok choi may not have a chance to really do well. If you are starting your bok choi indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Hillsboro. You should expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Hillsboro may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Hillsboro it frosts late in the year after April 15 so make sure that you are prepared to cover your bok choi in the event of a surprise late frost.

USDA Zone Info for Hillsboro

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 Hillsboro

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