Hydroponic Mediums

119Hydroponics is defined as the growing of plants through the use of mediums other than traditional soils.

This means that plant roots do not need to gather nutrients from the soil, instead taking it directly in from the water. Faster nutrient gathering is indeed one benefit of hydroponic systems. These systems tend to take up less room than traditional gardens, allowing people with limited areas to grow substantial amounts of food. One drawback is the volume of water and nutrients that are needed to propagate the plants.

One of the most important decisions for your hydroponic garden is the type of medium that you will use. Each medium has its advantages and disadvantages, as well as differing system types that correspond to each medium. Listed below are some different types of mediums for growth.

Rock Wool is the most widely used medium in hydroponics. It is made from molten rock that is heated and spun into filament fibers. In this process the medium becomes capable of capillary action. One disadvantage of rock wool is its classification as a possible carcinogen.

Perlite is volcanic rock that has been molten into glass pebbles. If not contained in plastic sleeves, the pebbles can float if a flood and drain system is utilized. Perlite can also be used in potting soils to decrease soil densities.

Pumice is a lightweight volcanic rock similar to perlite. It is readily available and relatively cheap. Sand can be used as long as it is sterilized between uses.

Sand is also cheap and readily available, however, it drains quickly, so plants need to be monitored closely.

Gravel can be used as long as the water and nutrients are continuously pumped through the medium. Any small gravel/pebbles are acceptable as long as they are thoroughly cleaned.

Polystyrene, commonly known as packing peanuts can be used for an inexpensive, readily available and green medium. Make sure they are not the biodegradable version as this can lead to decomposition into sludge.

Wood fiber can be used as an effective organic medium for hydroponics. It tends to keep its structure for a very long time, however, it can easily grow bacteria that harm plant roots. Care should be taken to monitor the cleanliness of the wood.

There are numerous other substrates that can be used for the mediums in any hydroponic garden including, brick shards, vermiculite, coir, and expanded clay. Any form of medium can work, depending on the type of system you are using and how extensive your knowledge