One of the first steps you take when you are determining 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 first chance to plant rock cress in San Juan can be figured out by reviewing the USDA zone info.

Planting Calendar for Rock Cress

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

You can plant rock cress much earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

The earliest that you can plant rock cress in San Juan 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 rock cress and expect a good harvest is probably October. If you wait any later than that and your rock cress may not have a chance to fully mature. If you are starting your rock cress indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in San Juan. You should expect an average low temperature of 25°F in the coldest months of winter.

It's important to remember that USDA zone info for San Juan may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in San Juan last frost occurs after February 15 be ready to protect your rock cress in the event of one of those late frosts.

USDA Zone Info for San Juan

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 San Juan

You may be interested in your other planting guides for San Juan.