Definition - What does Hydroponic Substrates mean?
Hydroponic substrates are used in hydroponic systems to anchor a plant's roots. Essentially, hydroponic substrates are various types of soilless grow media.
In a hydroponic system, there is no soil used. Instead, plants are supported by hydroponic substrates, which provide roots a point at which they can attach, help foster better aeration, and retain moisture. However, hydroponic substrates are mainly inert, so plants require a nutrient solution to provide minerals and other essential elements for growth.
MaximumYield explains Hydroponic Substrates
In a hydroponic system, plants are grown directly in a water-based, nutrient-enriched solution. There is no soil used at all. However, plants still need some sort of support for their roots and to help improve moisture retention. Hydroponic substrates are used for this purpose. There are four primary types of substrates used in hydroponics, although there are multiple options beyond these four.
Rockwool is one of the most common substrate options on the market. It is made from natural stone that has been melted and then spun into filaments. Rockwool works with most types of hydroponic systems, and can be used with plants of any type or size.
Perlite and vermiculite are also popular options. Perlite is made from igneous rock, while vermiculite is made from mica. Both are affordable, and work well with wick-style hydroponic systems. However, they are lightweight, and are better suited for new plants (seeds or cuttings).
Clay pellets are another popular option, and are sometimes called grow rocks, clay pebbles, Hydroton, or LECA. They work well with systems where watering is frequent, but do not retain much water.
Finally, coir/coco is another common type of hydroponic substrate. It is made from coconut husks, and can be purchased as blocks or bricks. It offers good water retention, and is completely biodegradable.
Other options on the market include peat moss, sawdust, sand, and gravel, although the four listed previously are the most commonly used.