One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

You should be able to estimate when it's the best time to plant purple rock cress by using the USDA zone info for Marion.

Planting Calendar for Purple Rock Cress

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

Purple Rock Cress can survive in pretty solid cold which tells us that you can plant them a lot earlier in the year than other plants that might not handle the cold.

The earliest that you can plant purple rock cress in Marion 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 purple rock cress and expect a good harvest is probably September. If you wait any later than that and your purple rock cress may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your purple rock cress indoors.

Last Frost Date

In Marion the average date of last frost happens on April 15. You can expect an average low temperature of 5°F in the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Marion and it is different every year. Half of the time in Marion there is a last frost after April 15 so just be sure to be ready to protect your purple rock cress if you have one of those late frosts.

USDA Zone Info for Marion

Here is the info for USDA Zone 7b.

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

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

Plants to Grow in Marion

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