Beginners Guide to Hydroponics
- Brenton Reilly
- Dec 15, 2023
- 6 min read
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Hydroponics, aeroponics and aquaponics are all methods for growing plants without soil. Most people are aware of the hydroponic gardening methods which include feeding plants with a liquid nutrient solution rather than the plant absorbing nutrients from the soil. Those interested in gardening will also likely be aware of aeroponic methods which involves spraying a fine mist onto roots of plants rather than submersing them in water like hydroponics. An aquaponics system can also potentially create a symbiotic (mutually beneficial) closed loop system between the plants and aquatic organisms such as fish. The objective with this system is that the fish will be creating the nutrient solution as their waste product, this will then feed the plants and the plants and growing medium can essentially filter and clean the water. Aquaponics may be more challenging for a beginner to setup as they may have to try and determine the correct sizes of growing beds, fish ponds or tanks and ratios of fish to plants ect.
Types of hydroponics
Ebb and flow (flood and drain) - Plants are periodically flooded with a nutrient solution and then the solution is allowed to drain away. This cycle repeats at regular intervals.
Material List: Growing tray, submersible pump, timer, drainage fittings and growing medium (e.g., hydroton, rockwool)
Drip system - delivers a nutrient solution directly to the plant's root zone via a network of tubes and emitters. The nutrient solution is dripped slowly onto the growing medium or roots.
Material List: Submersible pump, tubing, emitters/drippers, growing medium, timer (optional for automated systems)
Deep water culture (DWC) - Suspend plant roots in a nutrient solution, providing constant access to oxygen and nutrients. The roots are submerged in the nutrient solution, typically in a container or reservoir.
Material List: Reservoir/tank, air pump and air stones, net pots or baskets, growing medium (optional), nutrient solution
Nutrient Film Technique (NFT) - Use a shallow, sloped channel to continuously circulate a thin film of nutrient solution over the plant roots. The roots are exposed to the solution as it flows through the channel.
Material List: Channel/gutter system, submersible pump, tubing, growing medium (e.g., rockwool, oasis cubes), nutrient solution
Wick System - One of the simplest hydroponic methods, using a wick to passively draw nutrient solution from a reservoir to the plant's root zone. This method is often used for smaller-scale or passive hydroponic setups.
Material List: Reservoir, wicking material (e.g., cotton rope, felt), growing container, growing medium, nutrient solution
Aeroponics – A method that involves suspending the plants roots in the air and regularly misting them with the nutrient solution. Unlike other hydroponic methods which involve submerging the roots in water, this method allows highly oxygenated and nutrient rich conditions around the roots.
Material List: Container or growing chamber, misters, submersible pump, reservoir, tubing and fittings, timer (optional), growing medium, nutrient solution
Aquaponics - A sustainable method of food production that combines conventional aquaculture (raising aquatic animals such as fish, crayfish, or prawns in tanks) with hydroponics (cultivating plants in water) in a symbiotic environment. In an aquaponic system, water from an aquaculture system is fed into a hydroponic system where the by-products are broken down by nitrifying bacteria into nitrates and nitrites, which are utilized by the plants as nutrients. The water is then recirculated back to the aquaculture system, creating a closed-loop system.
Material List: Fish tank, grow bed, growing medium, water pump and plumbing, air pump and stones, fish
Important considerations
PH and EC (Electrical Conductivity) - PH in a hydroponic system can be measured via various methods including PH test strips and digital PH meters. PH plays a critical role in the health of plants as it can affect nutrient uptake. After levels are determined the PH can be adjusted to a more desired level using various additives.
EC – An EC or electrical conductivity meter can be used to find out nutrient concentration of the nutrient solution. The EC is directly related to the concentration of dissolved ions, this includes; nutrients such as nitrogen, phosphorus and potassium as well as micronutrients. It’s important to note that this may vary if you are using a natural or organic nutrient solution.
The recommended EC can vary depending on the type of plants you are growing (species), for example if they are fruiting plants like tomatoes or just leafy greens. The optimal EC may also vary depending on the stage of growth cycle the plants are in at the time. Measuring the EC is a useful indicator of the water quality, quality of nutrient solution and general plant health.
Lighting - The lighting for hydroponics can either be natural for outdoor or greenhouse hydroponics, or artificial. Light intensity reduces in winter which may require supplementing natural lighting with some artificial light when trying to extend the growing season for spring or summer plants. It may also be possible to use mirrors or mylar sheets to reflect extra light back onto plants. Research lighting and hours of daylight required for the specific plants you are trying to grow. For example tomatoes may require 12-18 hours of light per day as a constant requirement though out the growth cycle. This may be the equivalent of a particular 30W grow light placed 6 inches from the plant.
Growing medium - Different growing mediums will have different properties in terms of water retention and aeration. Using mediums such as coco coir will absorb much more water than clay pebbles for example. The medium should hold enough moisture to keep roots hydrated whilst not oversaturating them reducing aeration. PH may also be affected by various growing mediums such as coco coir.
Nutrient – Providing the right balance of essential nutrients is critical for plant growth in hydroponic systems. Understanding the nutritional needs of specific plants and maintaining an appropriate nutrient solution is vital.
Oxygen – Whichever system you use oxygen is an important component. Oxygen can be added to hydroponics via various methods, including airstones, sprinkler systems or fountains or cascading the nutrient though a piping sytem (eg NFT technique). In order for oxygen to be added to a system you essentially want to add dissolved oxygen into the water so that it is available at the root zone of the plants.
Temperature - If the nutrient also gets too hot there will also be much less dissolved oxygen in the nutrient solution. If you have an NFT system and the roots are submersed in water which is too deep this may also reduce the amount of oxygen. Maintaining appropriate temperature and humidity levels is important for plant health and preventing the growth of harmful pathogens.
Getting Started
Basic process for starting a hydroponic setup
1. Determine the plants you will be growing as this may influence the growing method
2. Choose your growing method (eg DWC, aeroponics, aquaponics ect)
3. Decide if you will be using a natural (organic) solution or synthetic
4. Decide if you will be growing outdoors or if you need lighting
5. Determine if you will try a DIY setup or if you will buy a commercial product
6. Determine the equipment required (make a list) or purchase a hydroponic kit and test
equipment for EC and PH
7. Research requirements for the specific plants you are growing (such as nutrient requirements, recommended ph &lighting requirements)
8. Start your setup with a few plants and add more when ready
Tips for success
Start with a simple system: If you're new to these techniques, begin with a small and straightforward setup. As you gain experience and confidence, you can expand and experiment with more complex systems.
Educate yourself about the principles behind hydroponics, aeroponics, or aquaponics. Learn about nutrient solutions, water quality, pH levels, plant requirements, and the symbiotic relationships in aquaponics. This knowledge will help you troubleshoot issues and optimize your system.
Choose the right plants: Not all plants thrive in hydroponic or aeroponic systems. Select plants that are well-suited for these cultivation methods, such as leafy greens, herbs, tomatoes, cucumbers, and peppers. Consider the specific requirements of each plant, including light, temperature, and spacing needs.
Get the lighting right: Adequate lighting is crucial for plant growth. Research the lighting requirements of your chosen plants and invest in high-quality grow lights that provide the appropriate spectrum and intensity. LED grow lights are popular for their energy efficiency and customizable settings.
Monitor and maintain water quality: Regularly test and adjust the pH and nutrient levels of your hydroponic or aquaponic system. Maintain proper oxygen levels and ensure good water circulation. Use a reliable water testing kit to monitor parameters such as pH, EC (electrical conductivity), and nutrient concentrations. ces to gain insights from experts in the field.
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