The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. 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 purple rock cress in Onalaska 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.

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

The earliest that you can plant purple rock cress in Onalaska 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. If you wait any later than that and your purple rock cress may not have a chance to really do well. You can get started a few weeks earlier by starting your purple rock cress indoors.

Last Frost Date

In Onalaska the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Onalaska may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Onalaska you get surprised by a frost after May 15 be ready to protect your purple rock cress in the event of a late frost.

USDA Zone Info for Onalaska

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 Onalaska

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