Manufacturers and suppliers of Gravel Flow Technique hydroponics systems for the home and commercial grower
FlowGrow Hydroponics (Pty) Ltd is a South African company situated in Crestholme (between Durban and Pietermaritzburg) in the province of KwaZulu-Natal, South Africa. We operate from a smallholding, and are commercial growers of a range of salad and vegetable produce. Our commercial growing operation has enabled us to evaluate and experiment with many of the hydroponic techniques that have been developed. The gravel flow technique proved to be the most practical, robust and efficient system, and our GFT system produces most of our output. Everything grows quickly, plants are of a uniform size, and all are of fantastic quality and taste. The labour requirement for the system is minimal. Over the years, many people who saw our system asked if there was a small domestic version available. They wanted to enjoy the benefits of the system without having to construct it themselves. After several years of careful research, our tray product, the first 'off the shelf' gravel flow system, was ready for the home market. We use only quality materials, and have made it easy to set up, operate and maintain, and it comes complete with an operating manual. If looked after as recommended, it will give a lifetime of enjoyable, fruitful cultivation.
For many years we have been assisting growers to set up conventional ground lay commercial systems. Over this time we have fine tuned the systems based on our own experiences and now manufacture a number of components which were previously not available pre-assembled. We are able to supply all materials and detailed manuals for the construction and operation of ground lay systems.
Hydroponics is a way of growing plants without soil. In soil-based agriculture, a good soil must provide a strong anchor, retain moisture and contain the right mix of plant nutrients. Not all soil meets these criteria for good plant growth, and hydroponics has allowed us to grow plants in places where the soil is unsuitable. Continual research has in fact made hydroponics an ideal method of achieving optimum results. It also costs much less to grow hydroponically than in the soil. This is why hydroponics has become so popular both for commercial and home use.
A number of different techniques have been developed, using a variety of different mediums. Common to all systems is the use of a nutrient solution which is water with the nutrients added. The techniques differ in the way they anchor the plant and deliver the nutrient solution to the plants' root system. Some techniques replicate the action of soil. The medium is watered on a cycle, and between watering the medium retains enough of the nutrient solution for the plants to use. This would include all top or bottom irrigated systems like drip irrigated systems and the flood and drain systems. These systems typically use pots, bags or troughs. Mediums like wood shavings, sand, vermiculite, perlite and expanded clay (leca) are used. Because the medium absorbs the nutrient solution it eventually rots and has to be replaced frequently. The flow techniques do not replicate the action of soil but instead deliver the nutrient on a continuous basis. This allows for the use of a non absorbent medium, such as the granite that our systems use.
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.