|Should I thin out some of the blossom heads that are in clusters on my|
|In theory, the fewer fruit a tree has to mature, the larger the fruits, but age of the tree is another factor in the size and quantity of fruit. It isn't necessary to thin the blossoms of your lemon tree, but you can if you wish. If the tree is very young it will go through a natural thinning process by dropping excess fruit (fruit it doesn't have the energy to support) all on its own.
Citrus trees are heavy nitrogen feeders, so make sure your fertilizer contains more nitrogen (N) than phosphorous (P) or potassium (K). Use at least a 2-1-1 ratio. Miracid Soil Acidifier is a water soluble product that works well and is a 3-1-1 ratio. You may be able to find specialized citrus/avocado fertilizer in your local garden center. Buy a good brand and apply according to package directions. Also important are trace minerals like iron, zinc, and manganese, so make sure those are included as well. Many all-purpose products will work. Follow rates on the package carefully as fertilizers come in different strengths, release rates, and application schedules.
Best wishes with your lemon tree!