Apple nutrient requirements

Bud Burst - Start of Flowering

• Nitrogen, Potassium and Magnesium – promote strong early growth of new plant tissues and maximum tree productivity
• Phosphorus – maximize root development and flower cluster formation
• Calcium – boost root and leaf growth and high yields
• Boron – maximize pollination and strong flower development
• Manganese – to maximize tissue growth
• Zinc – to optimize bud burst and early leaf development

Fruit Set - Fruitlet

• Nitrogen – in reduced amounts to maintain fruit fill
• Potassium – minimize fruit disorders
• Phosphorus – fruit set and development
• Calcium – maintain good fruit quality and minimize fruit disorders
• Magnesium – for reduced fruit drop
• Boron – improve fruit set

Fruit Fill - Maturity

• Nitrogen – in reduced amounts to maintain fruit fill and high sugars (excess can lead to rots and quality deterioration)
• Potassium – maximize fruit weight, TSS levels in the fruit and minimize disorders and sunscald (but at levels that don’t compete with calcium)
• Calcium – maintain good fruit firmness and storage quality
• Manganese – alongside Phosphorus will promote fruit coloration

Post Harvest

• Nitrogen and Potassium – boost reserves for next season’s early growth
• Phosphorus – maximize bud development and early rooting and new tissue growth in the following spring
• Calcium – maintain high levels in the tree
• Magnesium, Boron, and Zinc – replenish reserves and strengthen new buds