'Hydroculture' is a term which has largely been used to describe a style of hydroponics used and marketed by the German based company, Luwasa. This system relies on capillary feeding which involves the absorption of nutrients into the base of a medium followed by the upward movement by capillary action of those nutrients into the upper layers of the medium.
Two containers are used - one containing the plant in the medium and a second which contains the nutrient solution.
The container holding the solution has no holes whereas the one housing the plant has holes in the bottom. The plant container, which is smaller, is placed inside the nutrient container. Nutrient solution is placed in the container and maintained within predetermined levels.
By using a floater gauge on the side of the pots it is possible to see the level of the solution at all times without having to lift the plant pot out of the other container.
Luwasa use the expanded clay aggregate known as 'leca' or 'hydroleca', as their medium. Kits containing the two containers, floater gauge, and leca medium are available commercially in many countries. They are a foolproof and simple system of hydroponic culture but they are expensive. Luwasa initially concentrated on using this system for indoor plants, perhaps because that is an area where its cost can be justified. Containers are available in a broad range of shapes, sizes, and decorative colours.
Converting a soil-grown indoor plant to hydroculture:
Select a healthy plant and wash all the soil off its roots.
Fill about one third of the plant pot (smaller container) with expanded clay, or leca, and wash through with boiling water to clean and remove any dust.
Position the plant in the pot spreading the root system as evenly as possible, then cover with the remainder of the leca (which should also have been washed first).
Place this growing pot inside the outer container.
Slowly add nutrient solution until the floater rises to the middle of the marked levels.
For the first few weeks, be particularly careful to treat the plant well keeping it in a fairly well lit and moderately warm position. Humidity can also be very important at this stage if the plant is in a cooler climate. Once it has established the plant is largely treated as it would be in soil except you now have a very specific guide as to when it should be watered and how much water should be applied at a time.