Question
The older leaves on my orange trees are yellow and the branches on the middle top of the trees are dying. I believe these are symptoms of a lack of magnesium. I bought your epson salts and I'm not clear on how much to use. I don't want to use too much and kill the trees. How much should I use for a full grown mature orange tree? Should I spray it on the foilage or spray it on the ground?  

Answer
Jim,

First, you can not tell if your tree is Mg deficient by looking at it.  The only to determine this is to have the leaves tested at a lab.  Your extension office can do this.  You do not want to just start applying nutrients because you could make matters worse because nutrient deficiencies can have the same symptoms as toxicities.  Have some leaves tested and follow the labs recommendations.

Good luck

Gary