Apple trees have specific water requirements throughout their lifecycle. Proper irrigation is crucial in promoting healthy growth and maximizing fruit production. Inadequate or excessive watering can significantly impact the tree’s development and yield. Understanding the water needs at each developmental stage and selecting the best irrigation method is vital for orchard health.
How to water apple trees
The average young apple tree needs a lot of water in order to develop strong roots, leaves, and, finally, fruits. As a rule of thumb, young apple trees need more water than mature apple trees, which can rely mostly on rainwater in regions with frequent rainfalls. As a second rule of thumb, in regions with no frequent rainfalls, it is beneficial to irrigate apple trees (especially the younger ones) about once a week from late spring to fall (May to October, for the northern hemisphere). As a third rule of thumb, most apple trees need almost half of the annual water supply during summer (July and August, for the north hemisphere). However, these are just rules of thumb that should not be followed without doing your own research. Every field is different and has different needs. Although some general rules may apply, soil texture and climate conditions determine a great percentage of the amount of water needed in order to harvest a fair yield.
Water Needs by Developmental Stage
- Newly Planted Trees - Young Trees
Newly planted apple trees require consistent moisture to help establish their root systems. During the first year, water should be applied deeply around the root zone to encourage the roots to grow deep into the soil. New trees generally need around 19 liters (or 5 gallons) of water 1 to 3 times a week, depending on rainfall and soil type. Mulching can help retain soil moisture and suppress weeds. Inadequate water supply during the early years can lead to stunted growth and poor establishment. - Established Trees
By the second or third year, apple trees begin to develop more resilience to drought conditions. The trees generally require less frequent watering at this stage, but deep watering is still important. In drought periods or during hot summer months, mature trees need about 25-50 mm (1 to 2 inches) of water weekly. Soil type plays a key role here, as trees planted in sandy soil may need more frequent watering due to increased drainage. - Mature Trees
Mature, fruit-bearing trees demand regular watering, especially during key fruit development periods. Adequate moisture is crucial for the production of high quality fruits. According to the University of Minnesota Extension, water stress, particularly during the fruit set and sizing period, can cause poor fruit growth and reduce overall yield. Trees in their productive years typically require about 50 mm (2 inches) of water per week, especially during dry spells. It's important to monitor soil moisture and adjust the watering frequency depending on weather conditions and drainage.
Irrigation Schedule
The timing and frequency of irrigation are influenced by tree age, soil type, and weather. Generally, supplementary irrigation may not be needed if rainfall provides 25-26 mm (or 1 inch) of water every 10 days. In general, mature apple trees require around 500-510 mm or 20 inches of water during the growing season. If the farmer uses irrigation systems like drip irrigation and sprinklers, he/she can plan a more precise irrigation schedule with weekly applications tailor-made for their fields and crops. There are many available tools online to help you calculate the amount of water that should be applied per week.
Some general advice/suggestions:
- Spring - Development of buds/flowers and leaves: Watering should begin early in the growing season as trees emerge from dormancy. Deep watering every 7 to 10 days is ideal.
- Summer - Fruit development and maturation: During hotter months, trees require more frequent watering to combat evaporation and support fruit development. Mature trees may need up to 2 inches of water per week.
- Fall - pre and post-harvest: As trees prepare for dormancy, you can reduce watering but ensure the soil remains moist to help trees transition into the winter season.
- Winter—Dormancy: In dry winter climates, occasional watering, especially when the ground is not frozen, might be necessary to prevent root desiccation.
Both insufficient and excessive water can have detrimental effects on apple trees.
Trees experiencing water stress, particularly during the flowering and fruit set stages, are likely to have smaller, less developed fruit. Prolonged drought stress can result in leaf scorch, early fruit drop, and reduced growth. Over-irrigation, particularly in poorly drained soils, can suffocate the roots, leading to root rot. Overwatered trees may develop symptoms such as yellowing leaves and poor fruit quality. Proper drainage and avoiding standing water are critical in preventing these issues.
How to Irrigate Apple Trees - Irrigation Methods for Apple Orchards
Several popular irrigation methods are available for apple orchards. The choice depends on the orchard's size and design, the local climate (e.g., risk of frost or prolonged drought), the soil characteristics, the water availability and quality, and the available budget.
Drip Irrigation
Drip irrigation is one of the most water-efficient methods for apple orchards (up to 90% efficiency). It provides slow, consistent water directly to the root zone, reducing evaporation and ensuring water reaches the roots where it’s most needed. This method is particularly beneficial in regions with limited water supply, and it’s suitable for orchards in sandy soil. Drip irrigation also helps prevent diseases arising from water splashing on leaves or fruit and allows the application of soluble fertilizers (fertigation). However, the system has relatively high establishment and maintenance costs.
Sprinkler Irrigation
Nowadays, in the United States, sprinklers are used in at least 60% of apple farms. Their main advantage is protecting the tree buds from frost damage. Sprinkler systems are effective for larger orchards and are easy to automate. However, overhead sprinklers may cause water loss through evaporation, especially in hot and windy conditions. Under-tree sprinklers are a more efficient variation that minimizes evaporation and water waste while still providing broad coverage.
Micro-Sprinklers
Micro-sprinklers combine a sprinkler system's coverage with drip irrigation's precision. They provide localized watering to a tree's root zone, ensuring uniform water distribution with less evaporation loss. This method is increasingly popular in modern orchards due to its versatility and efficiency.
Flood Irrigation
While rare in modern commercial orchards, flood irrigation may still be used in some regions with abundant water supply and flat terrain. It involves channeling water through furrows to flood the orchard floor. While cost-effective, it can lead to significant water wastage and soil erosion.
How to Maximizing Water Efficiency in Apple Orchards
To ensure efficient water use and promote healthy tree growth, follow these best practices:
- Use Soil Moisture Sensors: Modern apple orchards benefit from using soil moisture sensors to determine when and how much to irrigate. This prevents overwatering and ensures that water is applied only when necessary.
- Irrigate Early in the Day: Watering in the morning minimizes evaporation and allows the tree to absorb moisture throughout the day.
- Deep Watering: Shallow watering encourages surface root development, making trees more susceptible to drought. Deep, infrequent watering promotes a stronger, deeper root system that can access moisture more effectively during dry periods.
- Mulching: Applying organic mulch around the base of apple trees helps retain moisture, reduces evaporation, and suppresses weeds. It’s a simple and effective way to improve water efficiency.
Effective water management is critical to the success of apple trees, from newly planted saplings to mature, fruit-bearing trees. Understanding the tree’s water needs at each stage and using efficient irrigation methods such as drip or micro-sprinklers can help optimize growth and fruit production. Regularly monitoring soil moisture and adjusting irrigation schedules based on weather conditions and soil type ensures healthy, productive orchards with minimal water waste.
To read more about apple tree cultivation, read the relevant articles below.
Apple Plant Information and Most Popular Varieties
Growing an Apple Tree from Seed
Apple Tree Propagation and Pollination
Site Selection for Apple Trees: Soil and Environmental Requirements
Watering Needs of Apples: How to Irrigate Apple Trees
Nutrient Needs and Fertilization of Apple Trees
Training and Pruning of Apple Trees
Major Pests and Diseases in Apple Trees: Identification, Symptoms, and Management
How to cultivate apples commercially
References
- https://www.mehrabyannursery.com/growing-guide/apple-trees/how-to-water-apple-tree/
- https://www.starkbros.com/growing-guide/how-to-grow/fruit-trees/apple-trees/watering?srsltid=AfmBOookOuwIrBqFuMrO-wzDNHEVIUI8awIhVLRmD4JzxZnELYNHF5SL
- https://www.starkbros.com/growing-guide/how-to-grow/fruit-trees/apple-trees/watering?srsltid=AfmBOookOuwIrBqFuMrO-wzDNHEVIUI8awIhVLRmD4JzxZnELYNHF5SL
- https://www.starkbros.com/growing-guide/how-to-grow/fruit-trees/apple-trees/watering?srsltid=AfmBOookOuwIrBqFuMrO-wzDNHEVIUI8awIhVLRmD4JzxZnELYNHF5SL
- https://nhb.gov.in/pdf/fruits/apple/app006.pdf
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- https://apal.org.au/wp-content/uploads/2019/09/fo-ow-handout-09-sept-irrigation-guidelines.pdf
- https://blog-fruit-vegetable-ipm.extension.umn.edu/2021/06/irrigation-recommendations-for-fruit.html
- https://apples.extension.org/effect-of-water-on-apple-trees-not-enough-or-too-much/
- https://www.sciencedirect.com/science/article/abs/pii/S0168192319301005
- https://treefruit.wsu.edu/web-article/irrigation/
- https://homeorchard.ucanr.edu/The_Big_Picture/Irrigation/
- https://onapples.com/blog/apples-and-water-a-natural-partnership.php
