Simply put, hydroponics is a method of growing plants in water that contains dissolved nutrients. In some cases, the plant roots are stabilized in a medium of clay or gravel, while in other cases the roots are suspended or partially submerged in water. In every case, the need for soil is replaced by a reservoir of nutrient-rich water, which eliminates water waste and reduces the amount of space needed for the plants to grow.
There are 7 different types of hydroponics system designs:
1. Basic Wick
The roots of the plants grow though a suspended aggregate medium such as gravel, perlite, or expanded clay. A wick (or some other type of absorbent material) connects the roots of the plant to the water nutrient solution to the bottom of the aggregate medium, giving the roots access to the nutrients.
2. Non-Recirculating (“Air Gap”)
The top half of the roots hang above the water, while the bottom half are submerged in the nutrient solution.
3. Raft, Float, or Deep Flow
Plants are suspended through Styrofoam rafts which float on the surface of the nutrient water. The roots are fully submerged in the water and an oxygen pump is required to give the roots oxygen.
4. Flood and Drain/Ebb and Flow
Plants grow in an aggregate medium, where the nutrient solution is constantly being pumped through and then drained.
5. Top Feeder
Plants grow in an aggregate medium which is suspended over a tank. The nutrient water is poured over the aggregate medium and drains through the bottom, where it is recycled.
6. Nutrient Film Technique
The roots of the plants are partially grown through an aggregate solution but the tips reach a slightly tilted trough. Water is poured through the trough and flows through, touching the roots.
Plants are suspended with the roots hanging in the air. The roots are then frequently sprayed with a bottle of nutrient solution.