Not more hardy, less. You can grow them in winter but have to plant in late summer. If well grown, they can withstand a few frosts but they will die if they have no protection when the really cold weather hits. Keep in mind in my zone we get lots of very cold temps, down into below zero, every winter. I'm in northwestern Virginia. So a good bit of the country is in my zone or colder.
20s is well below freezing, though. How's your annual rainfall? Even the hardiest stuff will die back or go dormant if it's too cold. You should be able to grow some hardy things with protection, though. Forget tomatoes and potatoes until summer, but kale, corn salad, turnips. Is your soil clay, rocky-sandy or rich loam? If you have good soil and decent rainfall, you should be able to grow lots of hardy things. With protection. Hardy plants hold up better if they're not stressed by drought, lack of fertility. Wet soil can cause root rot in winter in a lot of plants. Did you know if they're calling for frost overnight you can protect plants by covering them overnight - old sheets, cardboard boxes or you can get protective row covers at Lowes for really cheap.
Here's a quote for you:
My green thumb came only as a result of the mistakes I made while learning to see things from the plant's point of view. - H. Fred Ale
Carrots love cold and allow you to pick all winter long.
Not more hardy, less. You can grow them in winter but have to plant in late summer. If well grown, they can withstand a few frosts but they will die if they have no protection when the really cold weather hits. Keep in mind in my zone we get lots of very cold temps, down into below zero, every winter. I'm in northwestern Virginia. So a good bit of the country is in my zone or colder.
We get snow but not that much. If it dips into the 20s that is big news.
20s is well below freezing, though. How's your annual rainfall? Even the hardiest stuff will die back or go dormant if it's too cold. You should be able to grow some hardy things with protection, though. Forget tomatoes and potatoes until summer, but kale, corn salad, turnips. Is your soil clay, rocky-sandy or rich loam? If you have good soil and decent rainfall, you should be able to grow lots of hardy things. With protection. Hardy plants hold up better if they're not stressed by drought, lack of fertility. Wet soil can cause root rot in winter in a lot of plants. Did you know if they're calling for frost overnight you can protect plants by covering them overnight - old sheets, cardboard boxes or you can get protective row covers at Lowes for really cheap.
Here's a quote for you: My green thumb came only as a result of the mistakes I made while learning to see things from the plant's point of view. - H. Fred Ale