Proper irrigation scheduling is a tricky skill that surprisingly few landscape professionals have mastered. By far the largest loss of plant materials on new landscape projects is the direct result of improper irrigation scheduling. You may be surprised to learn that the most common irrigation scheduling problem is not too little water, or even too much water, it is watering too frequently. Many of the common turf grass and landscape shrub diseases are made worse by, or even may be the result of, watering too frequently.