When to Plant Purple Rock Cress in Harlan, IA

The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant purple rock cress in Harlan can be estimated by checking out the USDA zone info.


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.

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

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant purple rock cress
Possibly ok, but a risky time to plant purple rock cress
Probably not a good time to plant purple rock cress

The earliest that you can plant purple rock cress in Harlan 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. Any later than that and your purple rock cress may not have a chance to grow to maturity. Starting your purple rock cress indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Harlan the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -20°F.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Harlan and it will vary from year to year. Half of the time in Harlan there is a last frost after April 15 so be sure to be ready to protect your purple rock cress if you have a late frost.

USDA Zone Info for Harlan

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-20°F
Highest Expected Low-15°F

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

Plants to Grow in Harlan

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