Hydroponics describes a method of growing plants in a solution or medium without soil. Despite the name, the medium doesn't have to be water. It can be any nutrient solution or the inert substance like sand or perlite. Many people had their first exposure to hydroponics as children. Lots of kids would have a class project in which they stuck toothpicks in a potato and then suspended it in a jar of water. The potato's roots would grow into the water, while the shoots emerged from the part above the water. That was a decidedly low-tech version of hydroponics.
What will the gardener need?
A hydroponic garden will need a hydroponics system which is a structure that provides a place for growing plants and contains the water and medium. The system can be a tower, tray or A-frame, and it can have either a liquid (solution) culture or an aggregate culture. In the first type, the plant's roots grow directly in the water or solution; in the second, the plant is raised in a medium like sand or gravel. In both cases, the plant gets the water, oxygen, and nutrients it needs to grow.
The gardener will also need a medium, be it water or something like gravel. They will also need nutrients, a light source, and plants.
What kind of plants can be grown hydroponically?
Almost any houseplant, fruit or vegetable can be grown hydroponically. Liquid cultures generally work best for plants with shallow roots like lettuce, spinach, herbs, and radishes. Aggregate cultures work better for plants with deeper roots like beets or for plants that are top heavy like squash.
How safe is hydroponics?
Most hydroponic gardens are raised in a greenhouse. The high humidity in a greenhouse can increase the risk of salmonella contamination. Salmonella does cause food poisoning.
It is therefore prudent to at least wash the vegetables thoroughly to get rid of the bacteria on the surface. Cooking the vegetables is even safer since the heat destroys the bacteria.
One safety advantage that hydroponics have over conventional methods is that the plants need fewer chemicals. As they have few or no weeds, they don't need herbicides. Since many insect pests breed in the soil, plants raised hydroponically are also less susceptible to insects than are other plants. They, therefore, need fewer pesticides than do conventional plants.