This chart outlines various nutrient stress conditions many plants face. the direct symptoms are also shown as a condition of leaf damage. The symptoms can often help identify which nutrient is causing the stress. nutrient stress can be caused by both too little or too much of micro or macronutrients.
** HOW TO FIX NUTRIENT DEFICIENCIES IN GARDEN ** If your Veggies aren't doing well, despite you doing a good job preparing your soil, and watering and mulching enough--it may be a sign of a nutrient deficiency. Fruit and vegetables, plants grown in containers, and ones growing in very acid or alkaline soils are all at risk. Yellow or reddish colored leaves, stunted growth and poor flowering are all common symptoms of nitrogen, magnesium or potassium deficiency. (The Seed Guy)