Semi-hydroponics for growing orchids uses containers designed with a reservoir which maintains the water level, with a medium consisting of only clay pebbles. These pebbles have an excellent capillary absorption ability which allows them to draw the water from the reservoir and distribute it evenly to the entire root structure.
We fill the reservoir (simply pour in the top) with 1/4 strength fertilized water, approximately once per week. This gives the plant all the water and nutrients it needs at consistent levels. Watering is no longer a mystery, and is simple and time-efficient.
I have found tremendous advantage to growing with this method, with no disadvantage. Traditionally, orchids are grown usually in a pine bark mix or sphagnum moss. Since these will break down and compact over time, they require an annual labor of digging out all the old media and replacing it with a fresh mix. This disturbs the roots and can shock your plant for up to 2 months.
Watering in traditional methods can be tricky as well. It can be difficult to ensure all the roots are getting the moisture they need. Containers should have lots of ventilation and drainage holes so that the plant can be fully saturated yet not let the roots stay soggy too long.
Because the clay pebbles will not break down, this annual repotting is completely eliminated. Once a plant has adapted to the semi-hydroponic system, the only continuing care it needs is a larger container when the plant requires more space. Generally this is done when there is no room for new growths to emerge or the plant is starting to grow over the edge of the pot. By that time, the roots are so tightly wrapped around the pebbles that the plant can be transferred to its new container without any disturbance at all.
With little maintenance and care and no annual disturbance to the plant, it becomes easy to grow specimen-sized orchids that will fill your home with blooms.