Hydroponics Growing Media

Plants grown in a hydroponic setting require support and water just like any other plant. As a result of its name; many people who are new to hydroponics might be forgiven for thinking that plants are always grown in water. This is certainly done, but there are many other choices og media. Hydroponics is really just soil-less plant growing, with some other substance which provides the support and nutrients fed in ways other than through earth.

Using Rockwool

One of the most popular choices is a material called rockwool. This is a type of basalt that is specially processed to provide a strong, porous base. It is mostly inert, so it won’t decay or leach compounds into the water very much. Since it is porous, it provides good drainage. Rockwool is also lightweight and inexpensive.

Rockwool cubes are often used but small slabs are also available. There are pre-drilled holes in that allow for placing and growing seeds – any cubes containing plants that don’t survive can be easily removed. The cube can be cleaned and replaced with another seed to try again, or simply left out to provide additional space for the survivors. This way, the hydroponics tray can be regulated easily so that there are a limited number of plants competing for air, light, space and nutrients.

Despite its lightweight and porous nature, rockwool provides a very sturdy medium for growing plants. It gives good support to developing roots. At the same time it helps regulate the water temperature as it is a good heat conductor. Adding rockwool will alter the pH of the environment slightly at first, but this is easily controlled using a pH kit.

Though rockwool has many advantages for a hydroponic gardener, most people will want to experiment with different media at some time and there are a number of options available.

Using Sand

Ordinary beach sand is one common medium and it drains well compared to ordinary clay-infused soil. In a hydroponic setting however, it doesn’t do as well as most other possible media on the other hand it is extremely easy to use and certain plants take to living in sand very well. Certain orchid species in the wild, for example, grow naturally in wet sand.

Using Gravel

Ordinary aquarium gravel is used in some settings as it provides a strong, clean supporting medium that can also be attractive. But it can crumble and this means it will have to be cleaned and filtered well before use. Because it’s very heavy, a good pump will be required to keep air and water flowing through the system properly – otherwise, plant roots may dry out.

Using Perlite

Perlite is a more popular alternative than gravel. It is a type of volcanic rock that is heated to form small, lightweight pebbles resembling glass beads. Perlite is popular because of its ability to retain air. Since hydroponically grown plants will quickly deplete any dissolved oxygen, perlite will help the pump keep the water oxygenated.

Using Vermiculite

Vermiculite is similar to perlite as it is also made into small pebbles to provide a flexible supporting medium for hydroponic plants. It draws in water from passive systems by capillary action, and this in turn helps to automate the watering and nutrient feeding tasks. Since it holds even more water than perlite it may exclude air so it needs to be used in moderation. For this reason many people will use a mixture of perlite and vermiculite. If you are new to hydroponics then experimenting with different options can provide a lot of fun.