One of the first steps you take when you are estimating 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.

The USDA zone info for Hillsboro should be reviewed to figure out when it's the best time to plant rock cress.

Planting Calendar for Rock Cress

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

Since rock cress do well in cold you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant rock cress 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 rock cress and expect a good harvest is probably September. You probably don't want to wait any later than that or else your rock cress may not have a chance to fully mature. Starting your rock cress indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on March 15 in Hillsboro. In the coldest months of winter you can expect an average low temperature of 15°F.

It's important to remember that USDA zone info for Hillsboro is not always accurate and the actual date of last frost changes from year to year. Half of the time in Hillsboro there is a last frost after March 15 so make sure that you are prepared to cover your rock cress in the event of one of those late frosts.

USDA Zone Info for Hillsboro

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Hillsboro

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