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

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

The earliest that you can plant purple rock cress in Willmar is March. However, you really should wait until April 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 August. 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 few weeks earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Willmar. In the coldest months of winter you can expect an average low temperature of -25°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Willmar and it is different every year. Since half of the time in Willmar last frost occurs after May 15 be ready to protect your purple rock cress in the event of one of those late frosts.

USDA Zone Info for Willmar

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Willmar

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