This article is meant to help answer some important questions beginner growers might have when getting started, and while mastering hydroponics and different growing techniques. Most of these concepts are connected to each other, and you will need to connect to them too. The more we know, the easier it will be to grow!
BASIC HYDROPONICS PRINCIPLES
Hydroponic cultivation is the method that allows plant cultivation without soil, and can be achieved using different technique that share the same fundamentals. Plants requires light, oxygen and carbon dioxide while plant root systems require water, nutrients and oxygen. When plants are grown normally, water leeches nutrients out from the soil and carries them to the roots. Water and nutrients are sucked up by the roots to feed the plant optimal growth. Finally, soil drainage allows water to be replaced by air in the gaps between soil grains. In this circle the roots are supplied with oxygen.
In hydroponics, nutrients are dissolved in water, and soil is replaced with an inert growing medium in order to supply roots with the required elements. The nutrient solution is drip fed to each plant, rather than used to regularly flood and drain out the root chamber. Both methods require a timer and a pump for the nutrients to circulate through the roots.
Roots can also be grown in the air by spraying the with a fine mist of nutrients as it happens with Aeroponics. An other to grow can be by immersing the roots in the juice, as long as the solution is aerated under each root mass with an air pump. This method is similar to the NFT (Nutrient Film Technique) in which Rock wool act as a capillary mat. This eliminates the need to have flat bottom the root chamber and to level the bottom of the chamber, making it easier and cheaper to set up the system. This method where each plant has it’s own continuous feed will get the most vigorous growth.
The dripper is positioned on roots growing from the base of the seedling block, the roots will grow thick and more compact under the dripper. Drippers that handle up to 4 liters per hours are the most commonly used, still their drip rate depends on the pressure and will slow as the tank empties.
Feeding is also achieved with faster dripper at the top of each side of the root chamber. The plants grown with this system develop the largest root mass. The growth rate improve significantly by flooding more often up to each hour. After the root chamber is flooded it should drain to a trickle in a few minutes.
We have seen different ways to bring water to the plants, let’s now learn more about all these growing techniques in the specific:
- Nutrient Film Technique (NFT): Today’s most developed hydroponic systems use this technique where nutrients are fed into grow tubes for the roots to suck it up. The excess drains by gravity back the reservoir. A thin film of nutrient allows the roots to have constant contact with both nutrient and the oxygen within the air at the same time.
- Drip-Irrigation: Today’s greenhouse irrigation systems use the concept of drip irrigation. It minimizes water consumption maximizing plants grow. There are literally hundreds of dripping and micro spraying different devices on the market for the commercial and hobbyist grower to choose from.
A submersed pump feeds the solution through header tubes, and to secondary feed lines connected to drip emitters. The mount of solution is controlled and continuously drip-fed over the medium. By connecting an other tube to the lower part of the system the solution is recovered.
- Aeroponics: Plant roots are suspended in a highly oxygenated nutrient solution allowing inspection and pruning for the the roots. Air pumps or Oz injectors provide oxygen which is crucial for a healthy plant growth.
The simplicity and affordability of these soilless systems make them a popular choice among growers, and an excellent way to propagate cuttings.
In Aeroponics the roots are misted within a chamber where the pump pushes the water with nutrient solution through sprayers, keeping the roots moist while providing the maximum amount of oxygen.
- Deep Water Culture: The root system of a plant grown in Deep Water Culture is immersed in water, and bubbling aerator keeps the roots oxygenated. This technique is especially recommended for plants that are heavy feeders.
- Flood & Drain: Flood & Drain and NFT systems are very similar. They are ideal for multiple plant per square foot growing, where individual plant inspection would be difficult. They are also very popular as propagation method.
A plastic growing tray is flooded periodically by a submersed pump connected to a timer. the medium and the roots are soaked and drained at specific intervals. Various mediums suit for this system, but probably the most popular is the rock wool.
- Passive Planters/Dutch Buckets: This is probably the most commonly know form of hydroponics. These systems are minimalist and cheaper, do not require water nor the air pump.
This systems use a porous growing medium to support plant roots. Nutrients are in the base of the growing container allowing the plants to take as much or little water as they need.
Water level indicators show exactly when to add water and nutrients to the systems. These planters are possibly the easiest way to grow hydroponically in every kind of environment.