Limitations of Foliar Application Fertilizer
May 23, 2016

Foliar application fertilizer materials must be soluble in water. Most of these are salts and when applied in too high concentration the solution will cause "burning" of the plant tissue. Often the safe concentration of the fertilizer material in the solution is so low that repeated applications are required to supply the needs of the plant. This is especially true of nitrogen, phosphorus, and potassium. 

Foliar applications become soil applications if excess solution is applied or if rain falls shortly after application. This results in inadequate absorption of the nutrient by the foliage and loss of time, machinery use and labor for the application of the material. However, it is not a complete loss as some of the material that gets to the soil will be absorbed by the plant roots. 

Fertilizer materials are not compatible with all insecticides, fungicides, etc. If mixed with incompatible materials, loss of effectiveness of the fertilizer, the insecticide, etc. , or of both may result. In addition, this may also increase the danger of burning to the plant.