Tired of messy soil-based growing? Are you spending most of your time pulling out weeds from the unwilling land? Then hydroponics is the way to go! Hydroponics does not just refer to growing plants in water, as the name suggests, but covers a gamut of techniques that produce plants without using soil as a medium. That includes growing plants in water-based nutrient solution, in artificial hydroponic growing media and through aeroponics, where plant roots hanging freely in air are kept moist and nourished by spraying them with nutrient solution.
One uses hydroponic growing media to keep plants anchored; though there is no soil, some of your crops might need support to grow vertically. There are many inert materials used as hydroponic media to support plant roots.
Your choice of a growing medium is based on the kind of crop you wish to grow. The ideal hydroponic media provide your plants with good support; they facilitate air circulation and are moisture absorbent. Preferably, these media should also be pH neutral. Some common growing media include perlite, rockwool, clay pellets, coir, vermiculite, gravel and sand.
Volcanic in origin, perlite is a fusion of granite, obsidian, pumice and basalt. It is fused at extremely high temperatures. The final product is lightweight, like expanded glass pebbles. Perlite is useful because it can decrease soil density. Vermiculite of higher density compared to perlite. Perlite can be used loose or placed in plastic sleeves and immersed in water.
Vermiculite, also a product of super heating, expands into light pebbles. It has greater water content compared to perlite and is conducive to the easy delivering of nutrients in passive hydroponics systems. But this may affect air circulation, in which case vermiculite’s water retention properties may be lowered by mixing it with another medium.
The commonest and cheapest hydroponic medium is rockwool. Inert and easy-to-use, it works equally well in free drainage and re-circulating hydroponics systems. Made from molten rock, it is spun into thin clusters of fibre. The fibre makes it good for capillary movement and microbiological activity does not degrade it. A high density medium that improves the dispersal of nutrients and moisture, it creates optimum conditions for plant growth. It can be sterilized and reused, but most growers do not reuse a batch of rockwool.