Thanks Alex, this area is dry. I think I know the problem with botrytis. Once this season is over I'm going to mount them. All the peonies grow in the heap don't seem to have problem so far.
I save a big area for big watermelons, last year I grew the smaller varieties. I have some 25xgallon Gro bags for them too. It's an experiment for me. I never grew anything bigger than 10 pounds.