Four types of substrate you can use in your hydroponics system

18 July 2022
 Categories: Business, Blog


Choosing the right substrate for your hydroponics system is important to your growing success. The substrate does not contain any nutrients but will be the medium in which your plants will grow and where the roots will take hold. There are several types you can use.


One very popular medium is Rockwool. It is usually sold in cubes and is very permeable. This means it does not hold a lot of water but allows oxygen to circulate very well. It is particularly useful for germinating seeds, as the new plants can be moved from the germination area to the hydroponics system simply by carefully lifting the whole cube and placing it in its new position. The cubes are not biodegradable, but they can be reused by washing them in a diluted bleach solution and allowing them to dry.


The second type of substrate you can use is peat, although you will need to use peat that is specifically intended for hydroponics rather than the type used for potting. Peat is an organic substance that is very light and is good for plant roots. It will need to be kept damp though because it becomes solid when it is dry and will be impermeable. It works best when mixed with a harder material such as sand.


Perlite is a third type of substrate that is also often mixed in with peat to make a more permeable mixture. However, it can also be used on its own. It is an inorganic material derived from volcanic rock that is usually supplied as small balls and sold in bags, and it will provide good drainage for your plants. It can easily be reused just by rinsing it, although you can wash it in bleach if you need it sterilised.

Expanded Clay

Finally, expanded clay is often used as a substrate as it is cheap and easy to recycle. The balls of clay have large gaps between them which means there is plenty of room for oxygen to circulate and for water to drain. It is also highly absorbent and will stay moist, which will supply more water to the roots. Expanded clay can also be reused after it has been sterilised — there are many ways to do this but just boiling in water will do the trick.

Whatever substrate you use, don't forget that you will need to irrigate it regularly with a nutrient solution. If you are not sure what to use, your hydroponics supplier will be happy to answer any questions.

For more information, contact a hydroponic shop near you.