How Does Hydroponic Growing Medium Work?
The purpose of hydroponic grow medium is to provide support for the root system. It serves to provide oxygen, water and nutrients to the roots.
hydroponic growing mediumThere are three factors which contribute to the roots’ ability to grow in a substrate, these are pH, texture and nutrient content.
The texture of a given substrate is governed by its size and structure. A substrate with good texture will promote a strong root penetration, good nutrient uptake and high oxygen retention. Large particles of substrate will also allow for good aeration and drainage. If the substrate water retention is low then for an ebb and flow system for example, you’ll have to have an increased frequency of irrigation periods.
Smaller particles will of course pack closer together which will cause slower drainage. Whereas larger particles will drain faster and retain more air.
There are two main types of hydroponic growing medium; fibrous and mineral.
Fibrous Hydroponic Growing Medium
Fibrous materials such as peat moss, rockwool, coconut coir and vermiculite hold lots of moisture within their cells. These hydroponic grow media do not alter the composition of the nutrient solution. This makes these hydroponic growing media perfect for passive and ebb and flow hydroponic systems that absorb nutrient solution via capillary action.
Washing built up salt from your fibrous hydroponic growing medium, after you have removed your plants can be tricky and time consuming. Some fibrous mediums also lose much of their air holding capabilities after a crop. Therefore, with fibrous hydroponic growing mediums, you should replace them after each use.
Mineral Hydroponic Grow Mediums
These are mediums such as perlite, pumice, expanded clay, gravel, sand and pottery. The fact that they are mineral means that they do not react with living organisms or chemicals to change the integrity of the hydroponic nutrient solution.
With these hydroponic grow mediums you can wash salt which has built up, root fragments and other debris away for reuse. However be careful about low quality substrates shedding dust which may render it unusable.
You will need to keep this in mind and make a decision on the best hydroponic growing medium depending on what hydroponic system you use and what you’re growing.
Now it’s time to have a look at each of the main types of hydroponic grow mediums below.