Pruning
Pruning is a fundamental practice in hydroponic and aquaponic production systems that involves selectively removing plant parts such as leaves, branches, and shoots. This technique serves multiple purposes and plays a crucial role in optimising plant growth, health, and overall productivity.
Enhanced light penetration: In hydroponic and aquaponic setups, artificial lighting or natural sunlight is often limited in its reach. Pruning removes excessive foliage and opens up the canopy, allowing light to penetrate deeper into the plant. This is especially important for plants with dense foliage that might otherwise shade lower leaves and inhibit their photosynthesis. Increased light exposure results in more efficient energy conversion and better overall growth.
Improved air circulation: Pruning promotes better air circulation within the plant canopy. Adequate air movement is essential to prevent the development and spread of fungal diseases, as well as to reduce humidity levels that can lead to mould and other pathogens. Good airflow also aids in temperature regulation within the growing environment.
Disease prevention and management: Removing diseased, damaged, or infected plant parts is a key strategy for disease prevention. Pruning prevents pathogens from spreading to healthy plant tissue, mitigating the risk of disease outbreaks. Additionally, pruning helps create an environment that is less conducive to disease development due to improved airflow and reduced humidity levels.
Resource allocation: Plants have limited resources, including water, nutrients, and energy. Pruning allows growers to direct these resources to the parts of the plant that are most productive. By removing unnecessary or non-fruiting branches, the plant can allocate more nutrients and energy to the production of flowers and fruits, resulting in better yields and larger, higher-quality produce.
Structural support and training: Pruning helps shape the plant’s structure and growth pattern. It can be used to encourage vertical growth, prevent sprawling, and promote a more manageable and uniform plant shape. This is particularly important in hydroponic and aquaponic systems where space is often limited, and plants need to be trained to grow within defined parameters.
Energy efficiency: Pruning eliminates parts of the plant that may not contribute significantly to its overall productivity. This efficient use of energy allows the plant to focus its resources on developing and producing high-quality fruits, flowers, or leaves.
Harvest efficiency: Pruning can facilitate easier access to harvestable parts of the plant. Removing excess foliage and unproductive branches makes it simpler to identify and pick ripe produce, reducing the risk of damage during harvesting.
Optimal resource utilisation: In aquaponic systems, pruning helps maintain a balance between nutrient uptake by plants and nutrient production by fish. By controlling the size and nutrient demands of plants, growers can better manage nutrient cycling and avoid nutrient imbalances in the system.
In summary, pruning in hydroponic and aquaponic production systems is a strategic practice that optimises plant health, growth, and yield by promoting light penetration, air circulation, disease prevention, efficient resource allocation, and controlled structural development. It contributes to the overall success of these controlled-environment cultivation methods by creating an environment conducive to healthy, thriving plants.
Trellising
Trellising is a common practice in hydroponic and aquaponic production systems, involving the use of supportive structures like stakes, strings, or frames to guide and support the growth of plants as they climb vertically. Trellising is particularly important for certain crops due to their growth habits, weight, and overall benefits to plant health and productivity.
Vertical space utilisation: In hydroponic and aquaponic systems, where space can be limited, trellising allows plants to grow vertically rather than spreading out horizontally. Vertical growth maximises the use of available space, enabling more plants to be grown within the same footprint.
An example of a trellising system for cucumber.
Better light exposure: Trellised plants receive more uniform light exposure. By training plants to grow upward, leaves are less likely to shade each other, ensuring that each leaf receives adequate sunlight for photosynthesis. This results in healthier plants and more consistent growth.
Reduced disease risk: Elevating plants off the ground through trellising can help reduce the risk of diseases. When plants are in contact with the ground, they are more susceptible to pathogens, pests, and diseases. Trellising keeps plants cleaner and less exposed to potential contaminants.
Enhanced air circulation: Trellised plants benefit from improved air circulation around their leaves. This minimises humidity and reduces the chances of fungal diseases taking hold. Good air movement also prevents the buildup of moisture, which can attract pests and disease-causing organisms.
Preventing plant damage: Some hydroponic and aquaponic crops, like vining vegetables (e.g., tomatoes, cucumbers, beans), produce heavy fruits that can weigh down branches. Trellising provides support, preventing branches from breaking or bending under the weight of fruits. This prevents damage and ensures that fruits remain accessible for harvesting.
Easier harvesting: Trellised plants are easier to manage and harvest. When plants are vertically arranged, their fruits are more visible and accessible, reducing the risk of damaging or missing ripe produce during harvesting.
Better fruit quality: Trellising often leads to improved fruit quality. Fruits are exposed to more even light distribution, leading to uniform ripening and better flavour development. Additionally, fruits may have fewer blemishes since they are not in direct contact with the ground.
Space efficiency: For crops with vining or climbing growth habits, trellising can be a space-efficient way to grow them. Instead of sprawling out over a large area, trellised crops occupy a smaller footprint while still producing a significant yield.
Crops commonly trellised in hydroponic and aquaponic systems include tomatoes, cucumbers, peas, beans, and certain types of peppers. The trellising technique can vary based on the specific crop, system design, and available materials. By trellising appropriate crops, growers can harness the benefits of vertical growth, improve plant health, and optimise yield in controlled-environment cultivation.
Spraying
Spraying crops in hydroponic and aquaponic systems involves applying liquid solutions, often containing nutrients, pesticides, fungicides, or other beneficial compounds, directly onto plant foliage using sprayers. This practice serves various purposes and provides several advantages for the cultivation of plants in controlled environments.
Nutrient application: Foliar spraying is a method to deliver nutrients directly to plant leaves. While hydroponic and aquaponic systems provide nutrients through the root zone, foliar spraying provides an additional source of nutrients that can be rapidly absorbed by the leaves. This can be especially useful when plants exhibit nutrient deficiencies, as foliar spraying can quickly alleviate the issue.
Rapid nutrient uptake: Foliar spraying allows plants to absorb nutrients through their leaves, which have a large surface area and thin cuticle. Nutrients applied through foliar spraying are rapidly taken up by the plant and transported to where they are needed. This is particularly beneficial during critical growth stages when rapid nutrient uptake is essential.
Micronutrient supplementation: Certain micronutrients, such as iron and zinc, can become less available to plants under certain pH conditions or in the presence of excess nutrients. Foliar spraying with micronutrient solutions can supply these essential elements directly to the leaves, ensuring that the plants have access to them regardless of root zone conditions.
Disease and pest management: Foliar spraying can be used to apply pesticides and fungicides directly onto plant foliage, helping manage pests and diseases. This targeted approach reduces the need for the application of chemicals into the growing media or nutrient solution.
Stress mitigation: Plants can experience stress due to factors like environmental fluctuations, transplant shock, or physical damage. Foliar spraying with stress-reducing compounds, like seaweed extracts or growth promoters, can help plants recover more quickly and continue healthy growth.
pH and nutrient adjustments: Foliar spraying can also be used to make minor pH adjustments if the nutrient solution’s pH drifts too far from the desired range. Spraying with pH-adjusted water or solutions can help stabilise leaf pH and minimise nutrient imbalances.
Delivery of beneficial microorganisms: Certain beneficial microorganisms, such as beneficial bacteria and mycorrhizae, can be applied through foliar spraying. These microorganisms can help improve plant health, nutrient uptake, and disease resistance.
Experimental applications: Researchers and growers may use foliar spraying to test new compounds, treatments, or foliar fertilisers to evaluate their effects on plant growth, yield, and quality.