this is also something I want to learn more about.... a few thoughts:
1. I can read the standard explanations/thoughts but they still don't satisfy: http://www.uri.edu/ce/factsheets/sheets ... sfail.html
Trees seem to be more fickle and more mysterious than the literature suggests.
2. I have tried "scoring" the trunk....sometimes with success and sometimes not as a way of tricking the tree into producing.
3. I have tried epsom salts and fertilizers....so far, nothing to speak of.
4. A commercial grower friend I know uses a synthetic spray to get more fruit set, but I forgot the name right now and it may not be practical for homeowners.
5. I need to learn more about soil analysis, but lately the weather has been exceptionally wet and cool and this undoubtedly is affecting the pollination....(and I wonder if maybe even the bloom?) Hobby enthusiasts here in Washington are thinking they need to research more about varieties that do well with this kind of weird weather we have been having.
I am definitely interested in hearing how people may have treated old trees that they have pruned to get new wood, but the tree is still hardly producing any blooms or fruit....and what they could do to correct that situation as I am finding it with a lot of the trees I work with.