Flowgrow Hydroponics (Pty) Ltd Unclaimed

Gravel Flow Technique (GFT) is a variation of the Nutrient Film Technique (NFT) system which was developed in the early 1970s. The principle is that a balanced nutrient solution (salts and trace elements in solution) is made available to the plant root system as a 1 to 2 mm 'film' on the bottom of a gully. In conventional NFT systems, this is achieved by flowing the solution down a closed gully without the use of a medium. The plant root system is introduced to the film of nutrient solution in a net pot placed in an aperture in the lid of the gully. GFT does away with the gully lid, and uses a stone gravel medium in the gully. The use of this medium has several advantages. It acts as a 'capillary mat', effectively spreading the solution and allowing for wider growing troughs. It helps buffer the plant against changes in either pH or EC of the solution. It is a heavy 'anchor' for the plants, allowing large top structures to be supported in only 60mm of medium. It provides very flexible growing space as plants can be spaced in any pattern or density. Spacing is not restricted to the 'growing apertures' which occur in the NFT systems. Gravel is an ideal medium, being readily available, durable and inert. The bubbling effect of the solution as it passes through the gravel creates excellent oxygenation of the solution.