Kale is one of those greens that tends to just wilt up when you put it in the fridge. I follow a three-step process which drastically improves the life of kale: wash the kale thoroughly and then pat it dry with a clean kitchen towel; lay the towel flat on your counter and dry the kale on that; once it's dry (usually about 30-45 minutes) - wrap a paper towel around the kale, place in an airtight box or bag (like a salad leaf box). Squeeze all the air out, seal and then place back in the fridge.