Abstract:
Low cost appropriate technologies for efficient food production are very much in need for increasing population to grow their own food. Simplified hydroponics is an aggregate hydroponics system which can be used with limited resources such as space, water, energy, labor, time, cost etc. This technology is based on minimal inputs, requiring no green houses, commercial energy sources or expensive equipment. Simplified hydroponics systems are built with recycled or discarded wooden or plastic containers (boxes) filled with inert growing media, having a hole (about 1.5 cm above the bottom) on the container wall which helps to retain water and nutrients. This serves as a water and nutrient store for the plants, minimizing the wastage and also preventing environment pollution as there is no run off. Therefore, hand watering once a day with hydroponics nutrient is sufficient. The low input of labor has enabled this technology to be used by even physically and mentally challenged. This technology has now been adopted in twelve Latin American and African countries and International experience indicate that using simplified hydroponics technology, a 40 m2 space can provide a family of four with 500 calories each day, or over a pound of fresh vegetables for each. Therefore, it would be very much useful to test the potential of simplified hydroponics for urban food production in Sri Lanka as an appropriate, affordable, and accessible technology option. Three pilot projects have been conducted in Sri Lanka using a new nutrient formula developed by us and patented. The first project was to identify the suitability of simplified hydroponics system for the mentally ill and was conducted at Ridiyagama Mental Health Rehabilitation Centre. Twenty vegetable beds have been successfully managed by the mentally ill for a period of six months. The second project was conducted to test the adaptability of this technology to communities in Hambantota District involving ten households having limited space, for a period of six months, and was successfully completed. The third one was to quantify the space efficiency and to identify the suitability of the system to grow local crops utilizing a balcony space at Nugegoda. The results show that using a space of 3.6 m2, in 21 rigiform boxes (0.17 m2 each) having 2 plants /growing bed produced approximately 12.5Kg of total green harvest in a 4-5 month crop cycle. Crop varieties cultivated were tomatoes, brinjoles, bitter guard, long beans, cabbage, beans, okra, and Chinese kale. To produce that harvest the amount of hydroponics nutrients used was 18 liters/box for four month crop cycle costing approximately Rs.50 /box for nutrients. Simplified hydroponics can be recommended as a low cost technology suitable for busy office workers, house wives, elderly or disabled to grow vegetables within a limited space available. New designs, local low cost growing media, arrangement systems are yet to be identified to make this system more efficient.
