Agri Kultuur March/ Maart 2016 - Page 10

Article by Wynand Bezuidenhout Grow Machines Photos supplied B en van der Spuy and Gail Beresford of Benoni are the first people to have a fully solar driven Grow Machines NFT Trellis Crop System in operation. With a carbon footprint generating potential of nearly zero and using their plants to convert CO2 into oxygen they are most definitely looking after our world’s atmosphere and the welfare of food security in South Africa. This is certainly one of the most advanced hydroponic systems in existence and an example project for the future. Plants are produced in the soilless Grow Machines Nutrient Film Technique Trellis Crop System, a South African invention, powered by eight 300 Watt Solar Panels mounted on a sun tracking system. The tracking system follow the sun as the earth rotates ensuring a 90 degree sunlight contact angle that optimizes the energy output from the solar panels. It functions almost like a sunflower. The sun tracking system improves the panel efficiency with up to forty percent. To get away with minimal energy requirement and maximum efficiency, the solar system is combined with the variable speed tech- nology and optimized flow control system that comes standard with the hydroponic system. Ben has done some excellent research on solar tracking. His efforts will save them on energy requirements but most importantly, it will ensure that they have a reliable power source, an important requirement for Nutrient Film Technique production systems, available at all times. This will ensure that they don’t experience power related production losses. The hydroponic system was installed in December 2015. Ben and Gail have since made remarkable and “overwhelming” progress on their production operating their system like pro's...and pilots. Ben is a retired SAL Pilot and Gail was a SAL Flight attendant and manager. The system was installed on their 4 hectare plot in Benoni – Johannesburg. If all goes well with marketing they intend to install another system soon. At the moment they are growing multiple varieties in the system including cucumbers, lettuce, brinjals, cabbage, pak choi, tah tai, chinese cabbage, broccoli, peppers, chillies and some herb varie- ties. Some of the best performers include cucumbers, lettuce, pak choi and tomato varieties. Surprising growth rates have been achieved. Even seed suppliers were astonished by the amounts and quality of the fruits present on the plants. The hydroponic system was developed with special emphasis on providing growers as much as possible flexibility in terms of varieties that can be grown in the system. Its unique, internationally patented design allows all plants to receive near optimal but equal amounts of water, nutrients and dissolved oxygen providing an optimal root zone environment to the plants. The system was also designed in such a way as to maximize energy efficiency and minimize energy losses for heating purposes during winter times. Heat energy is only applied where the plants need it most…at the root zone. Optional features are available to cool down the roots zone during summer. This aid in keeping dissolved oxygen levels high, sugar to energy conversion for growth and transpiration high and pathogen levels low. The hydroponic system is also equipped with a unique nutrient