I previously wrote that I had turned comments off. I have turned them back on but I will see if allowing comments on any article for a restricted period of time solves the problem.
I know I can do this for each article, but I would like to be able to set this automatically.
I am not aware of any way to do this in WordPress. That is, I haven’t noticed any setting which permits comments for say, a week. I can probably do it in PHP. I would stick in a function which checks the posting date and depending on the number of days from the posting date to the date the article is displayed, then the function will determine if the comments box is shown or not.