After harvest: Science of growing better apples in Himachal

Among the 38 varieties of fruits grown in Himachal Pradesh, apple stands as the crown jewel, accounting for nearly 80 per cent of the total fruit production and generating an annual income of around Rs 6,000 crore. Despite this dominance, a major challenge continues to plague the state’s apple economy — over two-thirds of the fruit produced is small, extra-small or below the normal market size. Such fruit often fetches a much lower price, compelling growers to pack larger quantities per box, which further diminishes returns. One of the key reasons behind this problem lies in the lack of awareness about post-harvest management and unscientific use of nutrients in orchards.

The missing link in the apple chain

Most apple growers pay little attention to post-harvest practices, focusing mainly on the harvest itself. The use of unspecified fertilisers and nutrients without testing for deficiencies leads to nutrient imbalances and poor-quality fruit in the next season. In reality, the post-harvest stage is one of the most critical phases in an apple tree’s life cycle. Even after the fruits are picked, the trees continue to grow actively until temperatures drop below 12 degrees C. This period determines the tree’s readiness for the following year’s bloom and fruit set.

To prepare the orchard for the next season, several steps are vital — removing fallen leaves, weeds and diseased plant parts, preventing the overwintering of pathogens such as scab and maintaining proper sanitation in the basin area. Whitewashing of tree trunks protects against temperature fluctuations and insect attacks. Pruning helps maintain good tree structure and air circulation, while balanced nutrient application and pest management ensure the tree remains healthy through winter dormancy.

Why post-harvest nutrition matters

Post-harvest foliar nutrient management plays an indispensable role in strengthening apple trees, enhancing disease resistance, reducing stress after fruiting, and improving fertiliser efficiency. It also ensures consistent fruit quality and sustainable yields over time. Before initiating any nutrient management, it is essential to conduct both leaf and soil analyses to identify deficiencies or imbalances. Ideally, leaf samples should be collected during the second fortnight of August every year, while soil samples should be tested once every four to five years during October or November. These tests help growers design orchard-specific nutrient plans that replenish the depleted levels.

The nutritional concentration within the tree, built up in the buds during leaf fall, determines the potential for growth and productivity in the following season. Immediately after harvest, root activity is at its peak, which makes this the best time to provide key nutrients such as nitrogen, potassium, magnesium, zinc, boron and calcium. During the next bloom cycle, nitrogen and potassium stored from the previous year play a vital role in early growth and reducing biennial bearing tendencies.

Feeding the trees for tomorrow

Autumn is the most effective season for applying nitrogen to the floral buds. While it has minimal impact on fall shoot growth, it greatly enhances final fruit set. Urea applied at two per cent (4 kg per 200 litres of water) has been found effective at this stage. At least 40 per cent of the total nitrogen requirement should be supplied through post-harvest treatments. Foliar application helps optimise bud burst and early leaf development.

Since the soils in Himachal’s apple orchards are naturally rich in phosphorus, which depletes very slowly, it is generally unnecessary to apply it in autumn unless a deficiency is detected. Phosphorus supports spring tissue growth, early root formation, and strong bud development. Post-harvest boron sprays play a crucial role in enhancing new tissue growth in shoots, flowers, fruit and roots. They promote pollination, strengthen flower development and ensure better seed formation, which contributes to higher calcium levels in the next year’s fruit.

Magnesium is another critical nutrient because photosynthesis cannot occur without it. It facilitates energy transfer, protein and starch synthesis and helps in the uptake of phosphorus from the soil. Being a mobile nutrient, its deficiency first appears in older leaves. Zinc, too, is vital for chlorophyll formation and enzyme function. Zinc deficiency leads to poor auxin production, stunted shoots and blind buds. Post-harvest sprays are the most efficient way to introduce zinc into the tree. Mid-dormancy sprays of zinc sulphate, applied 15-20 days before bud swelling, can further strengthen the trees and prevent bud damage. Calcium, on the other hand, is essential for cell wall formation in pollen tubes and maintaining fruit firmness and shelf life.

Building resilient orchards

Practices such as orchard sanitation and whitewashing the tree trunks not only reduce pest and disease carryover but also help in building up the tree’s nutritional reserves. Burying fallen leaves near the drip basin and covering them with a thin layer of soil helps restore organic matter and improve soil fertility. This recycling of nutrients creates a healthier soil environment for the next season’s crop. Stronger trees with adequate nutrient stores lead to better fruit set, improved quality, and higher yields.

To manage overwintering pathogens and insects, a spray of copper oxychloride (600 gm) combined with horticultural mineral oil (2 litres per 198 litres of water) is recommended. It effectively controls pests such as red mites and reduces their eggs’ survival rate. Similarly, applying Bordeaux mixture one month before bud break helps prevent canker, bacterial and fungal infections that persist through winter.

In the current scenario, nutrient sprays should only be applied to orchards retaining more than 70 per cent of their leaves. In trees with greater leaf fall, spraying could trigger premature leaf and bloom growth, adversely affecting fruit set in the following season.

Towards sustainable apple cultivation

Scientific post-harvest practices are no longer optional but essential for sustaining Himachal’s apple legacy. From timely nutrient replenishment and disease control to improving soil fertility and tree health, every step taken after the harvest influences the next year’s yield. With careful planning and scientific intervention, Himachal’s orchards can continue to produce not just more apples — but better ones, ensuring prosperity for growers and premium-quality fruit for markets across the world.