Water Culture
Because they lack media to store water and nutrients, water culture systems need a continuous flow of nutrients to prevent drying out plant roots. Thus, the plants are more at risk from power outages and mechanical failures. But without medium, recurring costs and waste disposal are reduced and the balance of nutrient solution is uneffected. They also are more compact and lightweight than media-based systems. Stacked or vertical nutrient film technique (NFT) channels produce an amazing harvest in a surprisingly small space--and look nice too.
Although several different types of water culture systems are available, not all are appropriate for beginners. NFT is the most popular water culture system. This is a channel-type system where plants are supported with rockwool cubes, cups, or collars and their roots dangle in triangular pipes or round tubes. Nutrient solution runs along the bottom of the channels so just the root tips are submerged. The main portion of the rootball hangs in the air. Capillary mats are often used in the bottom of the channels to help distribute the growing roots evenly for better aeration. Hybrid, media-based NFT systems have media-filled troughs instead of empty gutters.
See the media-free jar system in the Easy Hydroponic System Plans section for a basic example of a water culture grower.
Further Reading