LECA, the acronym for lightweight expanded clay aggregate is a grow medium that is typically used in self watering hydroponic growing. LECA is an inorganic material that doesn't decompose like bark or sphagnum moss. It comes in different size round pellets which by their nature allow for air gaps and air flow through the growing space. Self watering hydroponic growing technique for orchids is relatively new in the world of orchid growing. Some growers and hobbyists like to grow in self watering hydroponic systems, this method can work if you have a very busy schedule or leave home for extended periods of time. However, it may not work with all species of orchids and beginners should wait until they have more experience with growing orchids before trying this method.
A self watering hydroponic system is basically a system in which a reservoir of water is within reach of the plant root system. Plants are placed in LECA in a container made specifically for self watering hydroponic growing. Today, there are a number of different containers on the market which with one can practice self watering hydroponic growing. Water is contained at the lower end of the pot in a reservoir and wicked up and absorbed through the LECA providing a constant source of moisture for the root system, yet remaining aerated due to the air gaps created by the LECA.
The beauty of a self watering hydroponic system is that it is low maintenance. You do not have to wait until the reservoir is empty to water, it is a good idea to refresh the reservoir once a week with a water/fertilizer solution. One main difference when it comes to fertilizing is to only use a non urea based chemical fertilizer with micro nutrients. Organic fertilizer may lead to the growth of algae or molds in a self watering system. Remember to use 1/4 of the recommended monthly feeding of fertilizer when fertilizing weakly, weekly.
One of the main benefits to using a self watering hydroponic system is convenience. If you have a busy schedule and do not have a lot of time to devote to caring for your orchids, or perhaps you have to go on frequent business trips where you are not home, a self watering hydroponic system for your plants may work well in your life.
There are some drawbacks to using a self watering partially hydroponic system. Self watering systems may work better in warmer climates or environments. Cold environments may lead to mold or algae growth. Some self watering pots are not clear see through, so it is difficult to monitor the roots which is important for orchid growers. Although most orchids can be grown this way, some may not perform well.