Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. 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 determine when to plant purple rock cress by reviewing the USDA zone info for Gillette.

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 do well in cold which tells us that you can plant them much earlier than other frost tender plants.

The earliest that you can plant purple rock cress in Gillette 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 fully mature. 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

On average the last frost when the weather gets warmer is on May 15 in Gillette. You should expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Gillette may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in Gillette you get surprised by a frost after May 15 be ready to cover your purple rock cress if you have a surprise late frost.

USDA Zone Info for Gillette

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 Gillette

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