Hydroponic Gardening – a Guide to Growth Mediums

Posted on: 23 October 2017


To many outside the world of gardening, the term hydroponics conjures up images of row after row of plants with their roots submerged in water. While it is true that hydroponics involves growing plants without the use of soil, it does not necessarily follow that no growth mediums are used.

In fact, many hydroponic gardeners make full use of a number of soil replacements. There are many reasons why gardeners use these mediums, but one of the most important is to provide a means of physical support for the delicate root systems of the plants. Some plants will grow quite well without any type of soil or soil replacement as well, but other species will do much better with a bit of support.

Providing a growth medium also helps the plants in the hydroponic garden to use oxygen more efficiently. In the world of traditional gardening, the roots of the plants would gather the oxygen they need from the soil in which they are growing. Using a growth medium helps the roots get the oxygen they need even in the absence of traditional soil.

In addition, growth mediums help to keep the plants well nourished, replacing the nutrients those plants would normally receive from the soil. While the fertilizer-enriched water used in hydroponic gardening provides many nutrients, some gardeners find that further enhancing the nutritional value of the garden helps the plants to thrive.

One of the great things about using hydroponics to grow plants is that gardeners have a wealth of choices at their disposal. Gardeners are free to choose from a wide variety of growth mediums and soil replacements, making it easier than ever to adapt to the needs of their plants.

Just consider some of the most popular growth mediums for the hydroponic gardener:


Vermiculate is a great choice for hydroponic gardening as well as traditional gardening. This mineral has the capacity to absorb enormous quantities of water, helping plants absorb the nutrients they need from the water in which they grow.


Often used in combination with vermiculite, perlite is a volcanic rock that is able to provide superior drainage and excellent aeration in the hydroponic garden.


Rockwool is made from a combination of chalk and a rock known as basalt. This popular material is very porous, allowing it to hold large quantities of both water and air.

Clay pellets

Made with baked clay, expanded clay pellets are also quite porous, able to retain both water and air very well. Expanded clay pellets are a cost-effective choice as well since they can be used over and over again provided they are sterilized before each application.

Coconut fibre

Coconut fibres are made using the outer husks of these tough plants. These popular fibres are able to provide excellent water and air retention. In fact, some organic and hydroponic gardeners prefer coconut fibres to the better-known Rockwool.

Aquarium gravel

Aquarium gravel is not just for fish tanks anymore, and a growing number of hydroponic gardeners are giving this material a try in their gardens. One of the factors behind this growing popularity is no doubt its cost — aquarium gravel is quite inexpensive compared to many other popular growth mediums. Even thou gavel can be a good choice; however, gardeners need to know that this material does not hold water nearly as well as Rockwool, coconut fibre and other more expensive materials. Those who wish to use this inexpensive alternative will need to make sure the plants in their garden have a steady supply of water and nutrients.

Hydroponic gardening is becoming increasingly popular with both hobby and commercial gardeners, but it is important for those just getting started to make the right choices. Growing plants without the benefit of traditional soil does not simply mean submerging their roots in a vat of water. In order to be successful, hydroponic gardeners will need to make sure all the needs of their plants—including oxygen, nutrients and moisture— are well met. The right growth mediums can help to supply all of these vital elements and help the garden to thrive.