What happens if you use too much NPK in plants?

Inadequate or unbalanced growth is what happens if you use too much NPK in plants.

Specifically, overuse of nitrogen, phosphorus and potassium most often can result from one of two situations. In one case, the plant cannot process the three macronutrients because they are too highly concentrated and therefore in an unavailable, undissolved form. In the other case, the plant receives the macronutrients in proper form, but so fast as to encourage unnaturally rapid growth that emphasizes lush foliage at the expense of flowering and fruiting.