When fertilizing palms the fertilizer should be broadcast in a circle around the palm, extending out to the drip line. This method is more effective and safer than punching holes for the fertilizer. The University of Florida recommends using an 8-2-12 + 4%mg fertilizer.
Under the Pinellas County Fertilizer Ordinance that is now in effect, fertilizers containing nitrogen or phosphorus cannot be applied to landscapes between June 1 and September 30. You could apply a potassium only fertilizer, such as a 0-0-16 analysis now, then apply the 8-2-12+ 4%Mg in November, February and May. This should meet the nutritional requirements of the palm adequately while complying with the fertilizer ordinance.
To correct a manganese deficiency (commonly called frizzle top) apply manganese sulfate to the soil. Suggested application rates vary from 8 ounces for a very small palm to 8 pounds for a very large palm growing in alkaline soil. You might arrive at an application rate by estimating about ½ pound of manganese sulfate per inch of trunk diameter up to about 5 pounds. Repeat applications can be made at 2 to 3 month intervals.
Water in any fertilizer materials (complete fertilizer, manganese, etc.) after application.