Q.Lemon tree
My lemon tree has lots of little lemons coming but they are all black. It’s been outside sheltered all winter and covered up. Can you please tell me if this fruit is no good do to the very cold winter we have had . Do I pick them off or leave them.

Black fruit would not be normal.
Check the tree for signs of Sooty Mold. Treat with Neem Oil.
https://www.gardeningknowhow.com/edible/fruits/lemons/common-lemon-tree-diseases.htm
https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm