12/04/2008 17:48 - (SA)
Soilless farming changing food as we know it
The saying 'you reap what you sow' goes a long way in the farming industry. Unfortunately, farmers don't always get their whole harvest. MOHAU MOKOENA gets down and dirty with a farming system called hydroponics that guarantees 100% of what a farmer sows.
REMEMBER the old childhood experiment involving an avocado, a couple of toothpicks and a glass of water? You would prick an avocado seed with the toothpicks and half-immerse it in a glass of water and a few days later roots would grow.
That is a way of planting referred to as passive hydroponics. Hydroponics is defined as the growing of plants in sand, gravel or liquid, with added nutrients but without soil.
Today, hydroponic gardening has becoming the hippest way to do farming in South Africa – it uses less water than conventional soil farming, growth is faster, you get more from your harvest, and it’s soil-free and therefore eliminates soil-borne diseases such as rot or cutworm.
Karabo Mosala, founding member of the Ekurhuleni vegetable farm, Kea Setshaba, can’t stop singing the praises of hydroponic farming.
“This type of farming dates back to the ancient civilisations of Sumeria and Babylon near the Nile River and scientific studies have since proven that hydroponics is an efficient way of farming,” says Mosala, whose farm is based in KwaTema.
Mosala says his knowledge of soil erosion made him want to avoid conventional farming and he started researching other ways of farming that would either minimise or completely eliminate erosion.
He went to Durban, where an NGO that ran a hydroponic farm (which uses sawdust as a medium instead of soil) put him in touch with Keith Tozer. Tozer, owner of FlowGrow Hydroponics Crestholme in KwaZulu-Natal, has been dabbling in hydroponics since the 1980s.
“While I was working as a computer installer in the Middle East I was introduced to the hydroponic system of planting. When I returned to South Africa I started using hydroponics to grow vegetables using a flow grow system I’d set up.”
“The flow grow – which is also known as the Nutrient Film Technique (NFT) – uses the flow of nutrients that are passed through the water to the roots of the plants by suspending plastic trays at a sloping position on an aluminium stand,” says Tozer.
There is, however, more than one method of hydroponic farming. According to www.simplyhydro.com there are six different types of soilless hydroponic systems.
They include wick, water culture, ebb and flow (flood and drain), drip (recovery or non-recovery), nutrient film technique and aeroponic.
Dew Crisp farm in Muldersdrift, west of Joburg, uses different methods for different types of vegetables.
Christine Wadman, a trainer on the farm, says they go for the gravel medium when planting a variety of lettuce. “For our vine produce, sawdust is used with a drip system. The drip system basically drips about 10 drops of water into the saw dust. The trick here is to keep the dust moist and not dry,” says Wadman.
The farm plants vegetables such as lettuce, celery, cucumbers, tomatoes and a variety of herbs.
Dew Crisp manager Dickson Mhlanga says hydroponic systems use about 70% less water than conventional soil farming. “Our planting area is at a slope. Water is pumped from the reservoir, which is placed at a higher level than the planting area. The water contains the nutrients which are used to feed the plants. The water travels down the slope and when it gets to the end of the slope it gets pumped back to the reservoir. Basically the water is recycled and comes back with more nutrients and the same cycle carries on,” says Mhlanga.
Wadman says organic farming should not be confused with hydroponics. “Organic uses no pesticides whereas we use government regulated pesticides,” says Wadman.
Though pesticides are used they have no effect on the growth rate of the plant. “During the winter the plants take five or six weeks to fully grow and summer plantations are quicker. They only take a month at the most,” explains Mhlanga.
He says hydroponics minimise many farming diseases and plants are easier to clean as there is only gravel to remove.
Mosala, a vegan, says putting hydroponically farmed food on the table means better health for all.
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