I love the Meyer lemon trees as they are the easiest to grow in cold climates. They are a bit of a sour puss when it comes to fruit drop, as you have found out. My guess is that you are waiting too long to bring your tree indoors. Try moving it inside in September and then place the tree in a the brightest window where it gets full sun. Meyer lemons do best in a winter greenhouse. You are feeding and watering correctly as these plants need a constant supply of nitrogen and moist soil. Osmocote is a slow-release plant food with the nitrogen that citrus crave plus micro nutrients like iron. Lemon trees often suffer from pale green or yellow leaves - with green veins if they are lacking in iron. We look forward to hearing from you next year when you enjoy a bumper crop of lemons - I see plenty of lemonade in your future. Keep growing, Marianne Binetti