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

By looking at the USDA zone info for Des Moines it's possible to estimate when you can plant purple rock cress.

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 earlier in the year because they are very cold tolerant.

The earliest that you can plant purple rock cress in Des Moines 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. If you are starting your purple rock cress indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Des Moines. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Des Moines is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Des Moines last frost occurs after April 15 so always be ready to cover your purple rock cress in the event of a late frost.

USDA Zone Info for Des Moines

Here is the info for USDA Zone 5b.

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

Plants to Grow in Des Moines

You may be interested in your other planting guides for Des Moines.