Structure Types
Enclosed production environments are designed to create controlled growing conditions for plants in hydroponics and aquaponics, allowing for year-round cultivation regardless of external climatic conditions. These structures vary in their design, materials, and technologies used, and their selection often depends on the specific climatic zone where they are located. Here are some of the different types of structures used and how they vary based on climatic zones:
A. Greenhouses
Greenhouses are the most common enclosed production environments. They are constructed with transparent or translucent materials, such as glass or polycarbonate panels, that allow sunlight to enter while trapping heat inside. Greenhouses protect against harsh weather elements like wind, rain, and extreme temperatures. In colder climates, the design of greenhouses often incorporates insulation and heating systems to maintain a suitable temperature for plant growth. In warmer climates, ventilation and cooling systems are important to prevent overheating. Greenhouses are versatile and can be adapted to various climatic zones by adjusting the level of insulation, ventilation, and temperature control.
B. High Tunnels (Hoop Houses)
High tunnels, also known as hoop houses, are simpler structures compared to full-scale greenhouses. They consist of a series of curved metal hoops covered with plastic or fabric material. High tunnels provide some protection from weather and extend the growing season, making them suitable for mild and temperate climates. In colder zones, additional insulation layers or row covers can be added to enhance temperature regulation. High tunnels are more affordable and easier to set up than traditional greenhouses, making them a popular choice for small-scale and local production.
C. Indoor Vertical Farms
Indoor vertical farms are enclosed structures that utilise stacked shelving or racks to grow plants vertically, often using hydroponic or aeroponic systems. These facilities are typically located in urban areas and use artificial lighting, such as LED lights, to provide plants with the necessary light for growth. Vertical farms are not dependent on external climate conditions and can operate year-round in a controlled environment. The temperature, humidity, and light levels can be precisely managed, making them suitable for a wide range of climatic zones, from extreme cold to tropical regions.
An example of an indoor vertical farm.
D. Climate-Controlled Containers
Shipping containers retrofitted for agriculture is another innovative solution for enclosed production. These containers are equipped with environmental control systems, including lighting, temperature regulation, and humidity control. They offer flexibility in terms of location and can be moved as needed. Climate-controlled containers are suitable for various climatic zones because they are designed to maintain optimal conditions regardless of external weather.
In various climatic zones, the design and technologies used in enclosed production structures will differ to adapt to specific challenges and opportunities. In colder climates, insulation, heating, and efficient temperature management are crucial. In hot climates, effective ventilation, cooling systems, and shading techniques become more important. Humidity control, pest management, and energy efficiency are considerations that apply across all climatic zones. The choice of structure will ultimately depend on factors such as the local climate, available resources, intended crops, budget, and the level of technology integration desired.
Necessary Equipment
A. Hydroponic Crop Growing
Growing crops hydroponically requires specific structures and equipment to provide plants with optimal conditions for growth. The necessary components may vary depending on the chosen hydroponic system, but here are the basic structures and equipment needed:
Growing system: The type of hydroponic system will determine the overall structure. Common hydroponic systems include Deep Water Culture (DWC), Nutrient Film Technique (NFT), Drip System, and Ebb and Flow (Flood and Drain) System.
Growing medium: While hydroponics doesn’t rely on soil, a growing medium is necessary to support the plants and hold their roots in place. Common growing mediums include perlite, vermiculite, coconut coir, and rock wool.
Nutrient solution: A properly balanced nutrient solution is essential for plant growth. This solution contains essential minerals and nutrients that plants would typically extract from soil. Hydroponic nutrient solutions are available in pre-formulated mixes.
Reservoir: A container to hold the nutrient solution. It should be lightproof to prevent algae growth and equipped with a pump for recirculating the solution in systems like NFT, drip, or ebb and flow.
pH and EC meters: These tools measure the pH (acidity or alkalinity) and electrical conductivity (EC) of the nutrient solution. Maintaining the correct pH and nutrient levels is crucial for healthy plant growth.
Water pump and air pump: In systems like DWC and ebb and flow, water pumps circulate the nutrient solution. Air pumps provide oxygen to the root zone, promoting healthy root development.
Grow lights: In indoor hydroponic setups, artificial grow lights (such as LED or fluorescent) provide the necessary light spectrum for photosynthesis.
Timers: Timers control the water pump, nutrient solution delivery, and grow lights. They help automate the growing process and maintain consistent conditions.
B. Aquaponic Crop Growing
Aquaponics combines hydroponics with aquaculture, so the necessary structures and equipment include components for both plant and fish cultivation:
Fish tanks: These tanks house the aquatic species, usually fish, which produce waste containing ammonia.
Grow beds: The grow beds contain the plants and are typically positioned above or beside the fish tanks. They serve as the hydroponic component where plants absorb nutrients from the fish waste.
Media or raft system: Aquaponic grow beds use media (similar to hydroponic growing mediums) or rafts to support plants and allow their roots to access nutrient-rich water.
Pump and plumbing: A pump circulates water from the fish tanks to the grow beds and then back to the fish tanks. Plumbing includes pipes, valves, and fittings to regulate water flow.
Biofilter: Beneficial bacteria convert fish waste into nitrates, which serve as nutrients for plants. The biofilter helps establish a healthy bacterial colony.
pH and EC meters: As in hydroponics, monitoring and adjusting the pH and nutrient levels of the system are crucial.
Aeration system: Both the fish tanks and grow beds need oxygenation. Air pumps and diffusers ensure adequate oxygen supply to the fish and plant roots.
Fish species: The choice of fish depends on the specific aquaponic system and local conditions. Common species include tilapia, trout, catfish, and perch.
Fish feeding system: Fish are fed to produce waste for the plants. The feeding regimen needs to be balanced to prevent overloading the system with excess nutrients.
Back-up systems: In larger setups, backup systems for pumps, aeration, and other critical components are essential to prevent failures that could harm both fish and plants.
The necessary equipment for hydroponic and aquaponic crop growing ensures that plants and, in the case of aquaponics, fish, receive the right conditions for healthy growth and optimal yields. The specific components and designs will vary based on the chosen system, scale of production, available resources, and desired crops.
Growing Systems and Approaches
Hydroponic and aquaponic production sites employ various layouts and approaches to optimise crop cultivation. Two common approaches are bag culture and bed culture. Let’s delve into these approaches and other layouts used in hydroponic and aquaponic systems:
A. Bag Culture
Bag culture involves using bags or containers filled with a growing medium (such as perlite, coconut coir, or vermiculite) to support plant roots. The bags are typically arranged in rows, providing flexibility in arranging the growing area. The nutrient solution is delivered through drip irrigation, and excess solution drains out of the bags. Bag culture is adaptable and well-suited for small-scale hydroponic or aquaponic setups, especially where space is limited. It allows for good root aeration and can be easily adjusted for different plant types.
B. Bed Culture
Bed culture involves using larger containers or troughs filled with a growing medium to create larger planting areas. Beds can be constructed from materials like wood, concrete, or plastic, and they are often positioned at waist height to reduce bending. The hydroponic nutrient solution is evenly distributed through the beds, and excess solution is collected and recirculated. Aquaponic nutrient-rich water from the fish tanks is pumped into the media beds, providing both nutrients and filtration as the plants absorb the nutrients and filter the water before it returns to the fish tanks. Bed culture provides ample space for plant growth, making it suitable for a wide range of crops. It is commonly used in commercial operations due to its scalability and efficient use of space.
C. Raft (Deep Water Culture) Systems
In raft systems, also known as deep water culture (DWC), plants are grown on floating rafts that rest on the surface of nutrient-rich water in a tank or trough. The plant roots dangle below the raft, submerged in the nutrient solution. This method offers a highly oxygenated root environment, as the roots are in direct contact with aerated water. Raft systems are often used for lettuce, herbs, and other leafy greens due to their simplicity and efficiency.
Floating raft hydroponic or aquaponic method.
D. Vertical Tower Systems
Vertical tower systems involve stacking multiple tiers of planting pockets or trays vertically. These systems are popular in urban agriculture because they maximise space utilisation. The nutrient solution is typically delivered from the top and trickles down through the tower, providing moisture and nutrients to the plants at each level. Vertical tower systems are well-suited for smaller plants like strawberries, herbs, and some types of greens.
E. Nutrient Film Technique (NFT)
In NFT systems, a thin film of nutrient solution flows along the bottom of channels or tubes, and plant roots are suspended in the film, allowing them to access nutrients. The nutrient solution continuously circulates, providing plants with water and nutrients while also allowing for oxygenation of the root zone. NFT systems are ideal for crops with shallow root systems, such as lettuce, basil, and mint.
The layout and approach chosen for hydroponic and aquaponic production sites depend on factors like the type of crops being grown, available space, available resources, and the desired level of automation. Each approach has its advantages and considerations, and selecting the right one is crucial for successful and efficient plant cultivation.
Climate Control Equipment
Climate control is a crucial aspect of hydroponic and aquaponic production, as it allows growers to create optimal growing conditions regardless of external weather. Different equipment and systems are used to regulate factors like temperature, humidity, ventilation, and light. Here are some of the key components:
Temperature control: Maintaining the right temperature is vital for plant health and growth. Several equipment and systems contribute to temperature control:
Heating systems: Heating systems like heaters, boilers, or radiant heating mats are used to increase the temperature in cooler environments. These systems ensure that plants have the warmth they need for optimal growth.
Cooling systems: Cooling systems such as air conditioners, evaporative coolers, or fans help regulate high temperatures by dissipating excess heat and maintaining a comfortable climate for plants.
Thermostats and controllers: These devices monitor the temperature and activate heating or cooling systems as needed. They ensure that the temperature stays within the desired range.
Humidity control: Controlling humidity levels prevents issues like mould, disease, and stressed plants:
Humidifiers: These devices increase humidity levels by releasing water vapour into the air. They are especially useful in arid environments or during dry seasons.
Dehumidifiers: Dehumidifiers lower humidity by removing excess moisture from the air. They are essential in preventing fungal growth and moisture-related problems.
Ventilation systems: Proper ventilation ensures a continuous exchange of fresh air and helps manage temperature and humidity:
Fans: Circulating fans promote air movement and prevent stagnant air pockets. Exhaust fans remove hot, humid air and bring in fresh air.
Air exchange systems: These systems ensure a regular exchange of indoor and outdoor air, maintaining optimal conditions and preventing the buildup of CO2.
Light control: Lighting systems are critical, especially in indoor hydroponic and aquaponic setups:
Artificial lighting: LED, fluorescent, and high-intensity discharge (HID) lights provide the necessary light spectrum for plant photosynthesis. Timers control lighting schedules to mimic natural daylight cycles.
Carbon dioxide (CO2) enrichment: CO2 enrichment enhances plant growth and productivity:
CO2 generators: These devices release controlled amounts of CO2 into the growing environment to ensure plants have enough carbon dioxide for photosynthesis.
An example of a CO2 generator.
Environmental controllers: Integrated environmental controllers manage multiple climate parameters simultaneously. They use sensors to monitor temperature, humidity, CO2 levels, and more, then adjust connected equipment accordingly.
Shade cloth and light reflectors: Shade cloth controls light intensity by blocking a portion of sunlight. Reflectors optimise light distribution, helping ensure that plants receive consistent light.
Automated systems: Many of these systems can be automated using advanced controllers and software. These systems monitor conditions and adjust equipment settings as needed, offering precision and efficiency.
Each hydroponic and aquaponic setup may require a unique combination of climate control equipment based on factors like the chosen crops, the local climate, the scale of production, and the level of technology integration. Effective climate control ensures that plants thrive and yields are maximised throughout the year, regardless of external conditions.