What is Hydroponics?

Hydroponics is a method of growing plants without using any soil. Plants needs sunlight, water and nutrients to be able to grow but they don’t need soil. Generally soil provides two important service, it provides a structure for plants to dig their roots into and it provides nutrition. The nutrients becomes available to the plants when they dissolve in water that flows through the soil. When the plants absorb this water they take those nutrients with them and use them to service their biological functions. Hydroponic systems provide these services in different ways. The water used in hydroponics has water soluble nutrients added directly to it so that plants always have easy access to the nutrition they require. Generally hydroponics systems break down into three main categories by how they receive their water.

  1. Deep water culture (DWC) – plant roots dangle directly into deep water
  2. Nutrient Film Technique (NFT) – plant roots dangle down into a thin film of water that constantly flows past the roots
  3. Ebb and Flow (or Flood and Drain) – plant roots are periodically flooded and drained

Other variations of each of these general configurations exist but they generally fit into these broader categories.

The plants also need to be physically stable. Generally plants sink their roots into a hydroponic grow medium for stability. Ideally these mediums do not affect water pH, and allow for consistent aeration of roots and retain water through hygroscopic forces. Commonly used mediums include expanded clay pellets, rock wool, coco coir and perlite but many gardeners have experimented successfully with gravel, sand and even glass.