I grew beets for the first time this year. They were looking very good indeed. But yesterday I saw that about 10 of them had separated where the stalk joins the root. Nothing seemed to have been eaten - squirrels are the only candidates - but the plants were dead. The remaining beets still looked very good. But today I see another 10 lying dead on the ground. This shows some of them: Does anyone know what could be causing this? I grow flowers but never succeed with vegetables so it is quite disheartening.