I think this subject would make a great forum!
I couldn't find the question about orange trees not bearing fruit, but I have some thoughts on that.
I feed my orchard only once a year in February 1 cup of fertilizer for every inch in trunk diameter.
It is specifically citrus fertilizer 13-10-4. The numbers represent 13 Nitrogen for green leaves 10 Potassium for strong root growth and health and 4 Phosphorous for good cell structure and health.
Green leaves on a citrus tree have adequate chlorophyll which is needed for trees to convert sun light to food the plant needs. The nitrogen accomplishes this, as well as 6 to 8 hours of sun light a day, which is optimum.
We normally only receive 27 inches of rain a year. In the Puna perhaps more feeding is necessary as the rainfall increases. We also have clay soil that retains nutrients and the lava in the Puna is so porous that perhaps more nutrients are necessary.
Here is a web site that might also have some useful information on non fruit bearing citrus.
http://www.fourwindsgrowers.com/solver/nofruit.html
Good luck with your citrus!
mella l
Edited by - mella l on 02/08/2007 15:12:27