I have grown a lemon and an orange from fruit I bought in a shop, and they are doing fine in plant pots. I then decided to grow a Kumquat, which is also doing well (I think) The problem is, I wanted to grow a free standing plant with a long stem and a bushy top, so I kept taking the lower leaves off. Now I have a top that can't be supported by a too thin stem. What do I do to get the stem to thicken out, or is it too late? best regards Tom I
Usually, I will recommend potassium silicate for strengthening stems, but in this case it could raise the pH to very unsafe levels for the tree. Without knowing your current soil pH, and being very precise with how much that you use in order not to fluctuate the pH, it would risk the health of the tree. So I can recommend CAREFULLY pinching the stem until you hear a light crack, and if it is too thick to do so, then lightly bend it back and forth up and down the entire height of the tree. This will lightly injure the plant to form a protective layer, but again, can be risky. Please include more information about the tree, and its environment, and I will be more than glad to help you.