Apple Nutritional Summary

Most nutrients are stored and retained as reserves in tree buds, bark and roots. These are then remobilized after winter to fuel leaf growth, flower bloom, fruit formation and growth.


Calcium, potassium and nitrogen are the most important macronutrients needed in productive orchards.


A significant proportion of nitrogen is used early season to provide good vegetative leaf growth, bloom and fruit set. Excessive, later applied nitrogen can adversely affect fruit quality.


Relatively low levels of phosphorus are required, but it needs to be available throughout the season. Phosphorus is particularly important during periods of new growth of plant tissue – e.g. when new roots and flowers are formed and during cell division in the developing fruitlets.


Peak potassium uptake occurs later than that of nitrogen. It is a key driver for yield but also has a major influence on fruit sweetness. Care has to be taken – particularly with later applications of potassium - that it doesn’t compete with and restrict calcium uptake otherwise bitter pit and related problems can occur.


Large amounts of calcium are needed within the tree to support healthy growth. While only a small proportion of all calcium ends up in the fruit, this low concentration is critical and it is important to maintain levels above 5mg/100g fresh weight at harvest in order to minimize storage quality problems. Fruit applications are usually needed to supplement soil-supplied calcium.


Magnesium is important in ensuring good growth, but at relatively low levels. It has a critical role to play in leaf growth and good flowering with minimal fruit drop.


While much lower concentrations of micronutrients are needed to satisfy good growth, boron, copper, manganese and zinc are key elements for apples production.


Boron has a critical role to play in bud development, flowering and fruit set, and is the most widely applied micronutrient.


Zinc also has a critical role to play in bud development, flowering and fruit set, like boron, and is the second most utilized micronutrient.