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When to Plant Purple Rock Cress in Iron Mountain, MI

One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Iron Mountain you can estimate when it's the best time to plant purple rock cress by looking at the USDA zone info.

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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 plants that might not handle the cold.

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 Iron Mountain 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. You probably don't want to wait any later than that or else your purple rock cress may not have a chance to fully mature. You can get started a few weeks earlier by starting your purple rock cress indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Iron Mountain. In the coldest months of winter you can expect an average low temperature of -30°F.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Iron Mountain and it can change quite a bit from year to year. Half of the time in Iron Mountain last frost occurs after May 15 so make sure that you are ready to protect your purple rock cress in the event of a surprise late frost.

USDA Zone Info for Iron Mountain

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)May 15
Average Date of First Frost (fall)September 15
Lowest Expected Low-30°F
Highest Expected Low-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Iron Mountain

You may be interested in your other planting guides for Iron Mountain.