Houseplant leaves with holes
The holes that line up in a neat row are probably created by mechanical damage. The dry edges and splits are probably caused by improper watering. Was the plant outside in the summer or do you have an animal in the house? The leaves look like they have more damage than the holes featured in the photo.
I have a large dog but the plant is out of reach for her. The holes where there when I brought it home from the store. The leaves have been having their edges die. You believe this is from improper watering? Too much or too little? I try to water the plant thoroughly once a week... sometimes once every two weeks. I've understood calatheas like to have the soil kept somewhat moist? Is this correct?
Drying leaf margins are a sign of not enough water or too little because the roots don't have enough or they have too much. Too much kills the roots and they can't take up water. Your plant is a tropical and humidity levels in homes in MN in the winter are very low. More frequent watering may be needed in winter. Watering the plant every week or more is probably necessary and tempering the water by letting it sit in a container so it is at room temperature before watering is important. Using distilled water is beneficial so that the pH of the water is right for the plant and the water does not contain salts and chlorine. Please read the entire fact sheet provided at the link, it provides very helpful information about how to improve the health and appearance of your plant. http://www.houseplant411.com/houseplant/calathea-how-to-grow-care-tips