Hydroponics: basic mistakes and how to avoid them

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In the second instalment of our series on alternative crop production methods, international hydroponics consultant, Prof Gert Venter, highlights common mistakes made by farmers.

Hydroponics-basic-mistakes-and-how-to-avoid-them
the 12 tunnels, equipped with boilers to maintain full production throughout winter, less than a year after commissioning.
Photo: courtesy of Prof Gert Venter

Poor planning and lack of management and commitment can result in certain failure when it comes to alternative crop production projects. This week we look at a project in Parys in the Free State that failed miserably within months of start-up, despite the participants all receiving some form of training before initiating the venture.

Job creation vs viability
The R6,8 million project was handed over to 12 inexperienced young growers to produce tomatoes, for which a contract was in place with one of the major supermarket chains.

The project was started with a ‘permanent’ labour force of about 35 labourers/ha, which is four to five times more than the norm of seven to eight labourers/ha for similar projects in South Africa.

READ Is hydroponics the answer to global food challenges?

It was even more out of line with the international norm of five labourers/ha for highly mechanised systems in some of the world’s most successful hydroponic tomato production units.

It was even more out of line with the international norm of five labourers/ ha for highly mechanised systems in some of the world’s most successful hydroponic tomato production units.

Over three months, the 12 growers planted one unit and part of a second before the project, consisting of 12 greenhouses, failed. The slow start-up had an immediate effect on liability as wages and salaries had to be paid over a long period before the project was supposed to come into production. This shows a lack of commitment to get the project to full production in the shortest period possible after start-up.

Not a single tomato was produced before all the plants died from lack of water when the electricity supply was cut off. None of the growers knew who was supposed to be responsible for paying the electricity bill. This should obviously have formed part of the initial planning for the whole project.

Business plan
When asked about the business plan, no one involved in the project even knew where it was.

For example, an inspection of the chimneys of the three boilers installed to maintain production through the winter months, as stipulated in the business plan, showed that they had never been used.

However, even this assumption was incorrect, as the main driving force for production is not maintaining high temperatures during winter, but providing adequate light for photosynthesis.

Even if summer temperatures could be maintained in a greenhouse during winter, the yield would still be much lower due to shorter day lengths, lower light intensities, and misty and cloudy conditions during this period.

Poor management
The fact that the 12 project members were unable to get the tunnels into full production within three months after start-up is a clear indication that neither the staff nor the growers were being managed.

It was also clear that there was no financial control, as questions about expenditure could not be answered by anyone, and no records were available to show how the start-up funding was allocated.

READ Scientific management – key to successful game farming

Other reasons for the project’s failure included inadequate maintenance of plants, allowing disease to spread, premature harvesting of unripe tomatoes, prolonging production with plants that should have been replaced, and poor management of infrastructure. The latter meant that the plastic floor covering, which was of poor quality, was allowed to deteriorate to such a degree that weeds became a challenge.

The following reasons were quoted in a press release after the project was closed down:

  • The unsustainable cost of transporting the produce over 500km to the market far exceeded the total income generated.
  • The project was never in a position to pay for municipal services such as water, land, and insurance, which amounted to an additional R600 000/year.

However, the following aspects were also ignored during the planning stages of the project:

  • It was launched in an area well-known for water shortages during drought, poor quality water due to high salinity, and the long distances involved in transporting produce to the major markets.
  • The greenhouses had inadequate ventilation for an area where summer temperatures reach highs of 40°C or more, requiring large fans to operate continuously.
  • Production systems were not well planned, as expensive, imported substrate was used for low plant densities.
  • Large passage areas between the beds reduced the potential production per square metre by more than 50%, negatively affecting the project’s viability.
  • Production systems with relatively low output potential were used instead of water-efficient hydroponic systems that could have increased yield by more than 500%.
  • Many other minor factors were overlooked from the outset.

In the rest of the series, I shall steer clear of the negatives and focus on the positive aspects of alternative crop production systems.

For more information, email Prof Gert Venter at [email protected].

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