I have a Macintosh apple tree about six or seven years old. I use horticultural oil after the last frost and early on it seems to do quite well. Every year I get lots of apples but by the time they get to be the size of a quarter or so they all fall off. How can I prevent that this year?
Certified GKH Gardening Expert
I would recommend fertilizing this tree once a year. This sounds like a phosphorus deficiency or maybe even a little potassium deficiency as well. Fertilizing once a year with an apple fertilizer will ensure that the tree has no deficiencies. Here is an article that will help: https://www.gardeningknowhow.com/edible/fruits/apples/apple-tree-feeding.htm