Growing Media for Hydroponics
Hi, I’m Shiran from Aqua Gardening
One of the first questions we get from hydroponic beginners is which growing media to use.
The grow media you select is more determined by the type of hydroponic system you have. First let me explaining what growing media’s are.
It is very much a personal preference, but there are some growing medias that are more suitable to a system, than others. The most common options are Clay balls, Perlite, Vermiculite, coco and rockwool.
Clay balls made from baked clay, they are porous and light which makes them great for drainage and transport. They suit any system that involves a continuous water flow like DWC, recirculating Systems and flood and drain. They hold little moisture.
Often they are used to aerate your soil or coco for better drainage, and you can even put a layer of them in any pot around the house, so plants cannot absorb any excess water from the bottom and get “wet feet”.
Perlite, is created by air-puffing volcanic glass to create an extremely light and porous material. It allows good drainage of water, but will also absorb it to an extent. It is great used alone autopot systems, wall gardens, NFT, drain to waste, and recirculating systems.
It is very common to mix it with vermiculite, or to combine it in a ratio of 30% perlite to 70% coco or soil. It’s not just a cheap way to bulk up the volume of your growing media, but also excellent for aeration in the root zone.
Vermiculite is another light media like perlite, consisting of a combination of minerals that are heated until they expand into flaky pebbles. When it is wet, it behaves like a sponge, the opposite to perlite which holds a lot of water.
Vermiculite can be used on its own for propagation, but it is recommended to mix with other media like perlite, coco or soil to encourage better water retention.
Coco is a natural fibre extracted from the husk of coconuts. It is also known as Coir or Coconut fibre. It’s usually a plain sterile medium, but lower quality manufacturers do not wash the fibres well enough, leaving salt in the product which can damage plants.
At Aqua Gardening we test any new brand of coco before it goes on the shelf. Coco is a great medium to use - it is porous for air, retains water well, but dries a lot quicker than soil, so you don’t risk in over watering.
Coco is ideal for systems using the method of run to waste, Autopot or as a general replacement to potting mix around the house. It is also a great medium for propagation. To give it even more aeration and better drainage, mix in 30% perlite.
Rockwool is made by melting rock and spinning it into extremely thin and long fibres. Once it is in its final shape, it contains many layers of fibres that create air pockets that allow good aeration and drainage. It should not be squeezed like a sponge as this destroys the air pockets and can choke a plant’s roots. Rockwool comes in many sizes for different stages of plant growth.
It is sterile, but often has a high pH, so before your first use it we recommend to soaking it in water buffered to pH 5.5.
It is great for propagation and you can transfer the small cube into any other growing media, or you can grow a complete plant using rockwool by inserting a small cube into a bigger one and then placing it on a larger rockwool slab for a base.
The last growing media I want to discuss are professional potting soils. Once you try any of these you will never buy another soil again. They are high in nutrition, and can be used over and over, with just a little top dressing. They can also be used in conjunction with liquid plant food to control the plant’s growth. They are not a hydroponic media, but more of a tailored potting soil for those from starter to professional levels.
Now you know all the types of growing media there are, you can choose which one will be the ideal one for your circumstances.
We have matched the best growing media to the different hydroponics systems:
For Run to Waste – use Coco coir, perlite & vermiculite, rockwool & professional soil – BUT not clay balls
For Recirculating & DWC – use clay balls only
For Flood & Drain – use Clay Balls, perlite or rockwool
We recommend you watch our Hydroponics Growing Kits video to find out which kit best suits you.
I’m Shiran from Aqua Gardening, for safe healthy food which grows itself!