D@ves Gardens says 20F for Mamillarria spinosissima .Others have it at 25F.I do see where 46F is mentioned as a minimum temperature. That might be a habitat minimum for the natural range that it is in. Mine has seen it below freezing but I take it in when it gets close to 30. All of this is given in a perfect situation, A dry in the ground situation and a brief period of the cold. Deserts plummet at night and warm back up i the day.Was your pot out in the weather and was the ground wet and how long was the freeze. The size of the pot will have the roots much colder than if it was in the ground. Also many cactus will automatically dehydrate themselves as a defense mechanism against the cold if they have been hardened of, and slowly rehydrate as it gets warmer. I do not know if this is what is going on. I would see if your soil its wet. I try to keep my cactus undercover, out of the rain when it gets under 40F. What is the soil mix like. Does it have a lot of drainage? Rot and cold are your enemy. 23 is cold. That is colder than all but the DG lowest rating. I guess this comes under the heading of learning to question authority. Eh? HINT, Do it politely and quietly after the appropriate research. I guess there is no better time to learn about your parents fallibility. We are all only human. Great lesson for life.. Hidalgo Mexico was mentioned as its natural range. One might see if one could find the plant zone for the area. Remember, many times hardiness can be more than where it lives naturally. But that is a starting place to understand rain patterns and also when to start being cautious. A lot of cactus grow in areas other that the high desert. Hidalgo is not New Mexico or Nevada. This post was edited by wantonamara on Sun, Nov 23, 14 at 19:12

don't know about your woodpeckers but i have a pair of lewis's woodpeckers who have nested here last 3 years. i also have lots of orioles and i put out fruit and jelly and watermelon for the orioles, the young Lewis's love the jelly and watermelon and eat lots of fruit and they come back every year. i also have downeys and hairys and flickers that use the same feeders as the Lewis's

If I remember correctly, you live in northwestern Indiana, right? I grew up there, and in the 1950's and 60's, these birds were very common. Their population diminished after that, and when I have been back, I haven't seen one for a long time either. Since they are insect eaters, and largely urban birds historically, I wonder if insecticides, etc., are at least possibly responsible for their decline. It would make an interesting study. Tucker

Looks healthy and happy! I am happy to see you post a bit, sending you healing vibes, take care of yourself.and keep in touch.