Hydroponics is a technique of growing plants without soil. Plants are grown in a soilless medium, such as perlite or coconut coir, and are fed a nutrient solution that is carefully balanced to provide the plants with all the essential minerals and nutrients they need to grow You can grow vegetables, flowers and fruits inside your home!
Growing plants in a jar with water can be considered a type of hydroponic system. However, if you want to grow healthy plants and have better results you should make a better hydroponic system; this can be as easy as a Kratky hydroponic system: In a Kratky system, plants are grown in a container filled with a soilless growing medium, such as hydroton or clay pebbles, and a nutrient solution. The plants are placed in the container in such a way that their roots are suspended in the nutrient solution. It does not require a continuous supply of electricity or pumps to circulate the nutrient solution, so it’s very basic.
Instead of using soil that needs to be watered, the hydroponic system completely replaces soil with the mineral nutrient solution. Not needing soil for plants growing means that hydroponics also has some advantages.
There are more types of hydroponic systems although all share the same principles of feeding the plants from a nutrient solution.
In this type of hydroponic system, the plant roots are placed in a solution of nutrient-rich, oxygenated water. This hydroponic system is probably one of the easiest to DIY, as it mainly done by using plastic buckets with the plant placed in a net pot suspended on the lid. The easiest deep water culture hydroponic system is the Kratky method which is a passive hydroponics solution. Kratly passive as it is a non-circulating technique where no additional inputs of water or nutrients are needed after the original application, and no electricity, pumps, or water and oxygen circulation systems are required.
The wick hydroponic system is using the same idea of putting the plants above the nutrient solution but the plant roots are not placed directly in the nutrient solution. Instead, a system of wicks are bringing the nutrient solution from the bottom reservoir to the above plants.
As the name suggests, the ebb and flow hydroponic system consists in regularly flush the plant roots with nutrients and air. At regular intervals, a simple timer causes a pump to fill the plants tray with nutrient solution, after which the solution drains.
Nutrient film technique is a Continuous-flow solution culture. A very shallow stream of nutrient solution is recirculated in a thin layer past a bare root mat of plants in a watertight channel, with an upper surface exposed to air. Unlike with deep water culture hydroponics, a stream (or “film”) of nutrient solution flows over the ends of their roots.
This system is similar with the watering drip systems used in regular agriculture. The aerated nutrient solution is pumped slowly through a network of tubes to individual plants. The quantity of the nutrient solution that is dripped is controlled precisely.
Both aeroponics and fogponics are replacing the immersion of roots in various quantities of nutrient solution with an aerosol of nutrient solution. The method requires no substrate as the roots are suspended in air and the roots periodically wetted with a fine mist of atomized nutrients.
Read more about the various hydroponic systems here
All the hydroponics systems, (maybe except aeroponics) require some sort of substrate. The hydroponic substrate is meant as a support for the plant and also has an important role in bringing the nutrient solution to the plant roots.
There are a lot of hydroponic substrates: