I have a 3 year old Nectarine tree in a pot. It looks healthy, has leaves, flowered and grew fruit. The fruit is about a quarter size or a little larger. They looked healthy up until about a week ago. Now they are shrinking and dying. The soil is about 2 years old. There are about 20 pieces of fruit. Some have already died and fallen off. Any help would be appreciated.
Nectarines Are Dying
Your tree is still quite young, and fruit drop is not unusual. This article, which is about peaches but would also apply to nectarines, will tell you more: https://www.gardeningknowhow.com/edible/fruits/peach/peach-tree-fruit-drop.htm