If you are not familiar with hydroculture, (German - hydrokultur) it is a close cousin to sub-irrigation. Instead of growing indoor houseplants in solid media that mimics natural soil (peat, or coir, bark, perlite) the solid media in hydroculture is clay in the form of pellets or balls.
Hydroton is the most widely (perhaps only) brand distributed in North America. Unfortunately we have no clay pebble kilns in North America. All of it is shipped from Europe.
All of the plants in the promotional video (below) for the German company Gärtner Gregg (Gardener Gregg) are growing in hydroculture. Hydroculture is widely used in the Netherlands and most of Europe.
The second video in German demonstrates how to convert a plant from soil culture to hydroculture. Anyone can do this. I have converted hundreds of soil grown plants to hydroculture with very little damage or loss. It is well worth doing.
Note the water level indicaters in both videos (the plastic tube sticking up). Rather then spending $3-5 for a float indicator, you can use a simple pipette method (click photo to enlarge). It costs next to nothing and is very simple to use.
If not for the fact that soil is the predominant media in the U.S. and a need to be relevant to this market, all of the plants in the CuGreen indoor plant lab would be growing in hydroculture.
It is a simple-to-use, hygienic and sustainable method. There is no end of life for clay pebbles. You can leave them to your children…along with the plants you grow in them.
Just like sub-irrigation, hydroculture is a simple form of hydroponics that does not require pumps and electricity to oxygenate the water (nutrient solution). Oxygen is introduced into the media from the ebb and flow design of the system.
As the water level in the media goes down, the oxygen supply goes up. Air replaces water. Similar to SIP watering let the water level go down to empty or almost empty before refilling. It’s that simple.
Green house growers all around the world use a similar method called ebb and flow irrigation. The plants, sitting on watertight benches or on a concrete floor are flooded periodically.
The water drains after a short period of time, is stored and recirculates at the next flooding interval. Some of these systems use capillary matting. With these systems, there is no run-off or wasted water as in traditional overhead irrigation.
The U.S. houseplant industry is not likely to convert to hydroculture growing so you need to do it yourself. I believe there is a business opportunity for a wholesale distributor to provide hydroculture conversion as a service.
I have thought many times of doing it as a retail service in a new form of modernistic indoor plant store. The plants wouldn't be the cheapest. They would, however, be of the highest quality, easiest to maintain and affordable for a majority of the market. They would be particularly attractive for those who think they have a black thumb.