Christina Auerbach waters the newly planted organic vegetable garden. Pictures: Supplied
Christina Auerbach waters the newly planted organic vegetable garden. Pictures: Supplied

Getting off grid, harvesting rainwater

By Raymond Auerbach Time of article published Oct 24, 2017

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Having moved from KwaZulu-Natal to George seven years ago, I set up research projects into water-efficient organic farming systems for southern Africa at the George Campus of the Nelson Mandela University, where I teach soil science and plant production.

My doctoral research in KZN in the 1990s showed how to reduce irrigation requirements using rainwater-harvesting techniques and I was rather surprised that there was little interest in my results at the time, even from the Water Research Commission, which had sponsored the research.

Our little organic farm near Durban had shown a useful model for small commercial farmers, and my Rainman Landcare Foundation trained hundreds of farmers in organic techniques, until we had to close down due to government non-payment of a training contract.

Three years ago, Christina and I moved into a new home in George, which we bought two years ago and we decided to work out on a small scale how water could be used efficiently while maintaining a comfortable life-style and producing healthy organic food on a small scale. 

Energy efficiency was also to be part of the mix, and we decided that we wanted to keep the swimming pool as well.

The house already had two 2500 litre tanks and a small electric pump. During the first year, we put in a more efficient electric pump and last year, a third tank, which immediately meant that the pool could be topped up with rainwater.

This year, we set up the new vegetable garden (in raised beds, as neither of us is growing younger), put in a solar-water heater and connected the whole garden to a bath-water irrigation system using the new pump. We also put in a fourth, smaller (500l) tank in the front, where it also had to look good, for aesthetic reasons.

The vegetable garden is also aesthetically pleasing and far more labour-efficient than most gardens, as well as being water-efficient and just enough work, together with our bicycles and swimming pool, to avoid us having to pay gym membership.

Raymond Auerbach with a solar-powered water pump, Anastasia Caude (French post-graduate student) and Ian and Natasha Strydom who installed the solar-water heater, tanks and garden beds.

The system is fairly simple, but had to evolve organically: a small pump fills the solar-water heater with rainwater, which is then heated by the sun. 

When I come home from the university, I fill up a luxurious bath with solar-heated rainwater, and enjoy a good read while destressing. 

The next morning, once the water is cool, we draw a few buckets of water out of the bath for flushing toilets and then irrigate the veggies and the flowers with the bathwater.

Before this, we have our short bicycle ride and then 10 lengths of the pool and whatever other exercises we feel like doing. 

And after meditation and breakfast, we are not only glowing with health, but feeling exceedingly virtuous in our extravagance. We have managed to cut our water use in half over the past six months, and our energy use is also about 20% less.

Energy saving is due largely to reduced water-heating costs, but also to LED bulbs, energy-efficient appliances and a geyser blanket. (We still have the electric geyser as a back-up, and only use the solar heater for the bath and outside shower. My philosophy is “start with the low-hanging fruits”, do the easy, cost-effective things first.) The compact veggie garden (5mx3m) was planted three weeks ago, and we look forward to our first harvest.

When Eskom fails us, we cook on our gas hob, enjoy our solar-heated rainwater, and have a romantic candle-lit braai on the verandah. 

And yes, we braai grass-fed beef or game, organic where possible (and which is not feedlot raised using grains which should be feeding people - feedlots use grains and other concentrate feeds which take a lot of water to grow; grass-fed animals have a far smaller carbon footprint, and combine the natural capacity of grasses to store solar energy, with the ability of herbivores to digest grass and turn it into food).

A comfortable lifestyle does not have to destroy the planet but setting up the alternatives does take some capital, knowledge and ingenuity. 

Much of the ingenuity here came from Ian Strydom, who helped us with the installations, but the cost was not as extreme as we had initially thought. 

We had had a quote of R225 000 to take our home off the grid with solar panels, an inverter and a bank of batteries, and this was way beyond our means. The total cost of our system (installed) including the cost of the tanks and pump which we inherited with the house, has been about R37 000 over three years. 

Savings in water and electricity are significant, considering that we would be paying penalty tariffs on our water consumption given the drought.

But even without this factor, we are saving about R200 per month in water bills and R300 per month in electricity. 

It will take us a while to recoup the cash investment, but we do not think that water or electricity prices are going to decrease anytime soon, and we also believe that every South African should be using resources consciously.

The southern Cape is particularly blessed with all-year-round rainfall, and we have not yet run out of rainwater once, though a few months ago, two of our (then) three tanks were nearly empty but given our roof area, 10mm rainfall generates more than 5 000 litres. 

So, after a couple of rainy days all our tanks were filled (total 8 000 litres storage), and this is enough for about three months of careful use.

The worst scenario was having to cut back to three baths a week when the tanks were low, and having to use a gas booster when the sun did not grace us with enough radiation to heat up the water.

An additional set of benefits has been the pleasure that we take in our garden and our water system, and our feeling that we are part of the solution rather than being part of the problem in building a new, more sustainable South Africa.

We are working with 500 gardeners in the informal areas and the townships around George, where a new generation of urban gardeners is setting up water-efficient organic gardens with the help of a team which includes City Health, George Municipality, Wessa, Landmark Foundation and the Garden Route Botanical Garden’s Environmental Education Centre.

Raymond Auerbach is professor of soil science and plant production at the George Campus of Nelson Mandela Metropolitan University; he runs the African Organic Farming Systems Research programme with funding from the National Research Foundation, the Centre of Excellence in Food Security, the German government and the Africa Earth Observatory Network.

He will present some of the results of the long-term comparative organic farming systems research trials at the Organic World Congress in India next month (visit and 

A non-scientific account of his research can be found on The Conversation (Organic farming gets a bad rap. Why it shouldn’t - see gets-a- bad-rap-why-it- shouldnt-65736).

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