Pro tips from a 100-tunnel cucumber farmer

Tunnel production may seem a relatively simple and profitable way to farm, but it involves high capital costs and has a narrow margin of error. Nico Laubscher Jnr spoke to Glenneis Kriel about the lessons that he and his team have learnt at Alzanne, near Vredendal, over the years.

Pro tips from a 100-tunnel cucumber farmer
Thanks to the Vredendal’s warm winters, the tunnels do not have to be heated.
Photo: Glenneis Kriel
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A little over three decades ago, Nico Laubscher Snr planted cucumbers in tunnels on his farm near Vredendal in the Olifants River Valley to add value to land too marginal for wine grape production.

The cucumbers turned out to be so profitable that he later uprooted several vineyards to expand production.

Today, his farming enterprise, Alzanne, has over 100 tunnels covering an area of roughly 10ha in total, making it one of the largest cucumber producers in the country.

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Replicating this success under the current production and economic environment would be near impossible, according to Laubscher’s son, Nico Jnr. He explains that his father’s first six tunnels paid for themselves within a year, allowing him to use the income generated to subsidise expansion.

However, the return on investment has been slower since 1998, when they purchased their first multi-span tunnel with wet pad and fans for automated climate control. They bought another in 2004, and a third in 2006.

“The cost of multi-span tunnels combined with rising labour, electricity and input costs, has become so exorbitant that it no longer justifies the investment if you’re going to produce cucumbers. The price of cucumbers is less than half of what it was three years ago,” Laubscher Jnr says.

‘Start small’
Another challenge is that the margin for error in tunnel production is much narrower than for crops grown in the open air. His advice to other producers keen to venture into this type of farming is therefore to start small, perhaps with second-hand tunnels, and to expand production systematically as they gain experience.

Nico Laubscher Jnr standing among cucumbers ready to be harvested.

Apart from this, the demand for cucumbers in the Western and Eastern Cape is limited, so merely ‘dumping’ the crop on the municipal market can backfire and cause prices to collapse. Farmers should secure a market before buying or planting anything.

One way of overcoming the market and skills problem is to team up with an existing supplier. Alzanne itself is part of such an initiative.

The enterprise partnered with 10 of its employees in 2009 and, with the help of the Western Cape Department of Agriculture and Exxaro Namakwa Sands, constructed two greenhouses measuring 0,25ha and 0,5ha respectively.

Alzanne carried most of the operating costs until production became economically sustainable, which took about six years. Shareholders have received dividends from the project since 2012.

Clearly, the larger the tunnel, the more expensive it is, but a higher tunnel is generally better, as it allows for better air circulation and climate control, says Laubscher.

A tunnel can last many years, particularly if it has been manufactured by a qualified company and is not subjected to adverse weather conditions such as frequent, strong winds.

These can damage both the fabric and the supporting structure as well as negatively affect production.

Plastic usually lasts about three years before it has to be replaced. “The structure has to be maintained to prevent holes and weaknesses from causing irreparable damage,” says Laubscher.

Thanks to the area’s warm winter days, there is no need to heat the tunnels, which saves money. Nonetheless, electricity still accounts for 20% to 30% of production costs, depending on whether a structure makes use of natural or controlled ventilation and climate control.

Being on Eskom’s Ruraflex electricity plan helps reduce irrigation pumping costs in vineyards, but is not really a factor in tunnel production, as plants are irrigated eight to 12 times a day depending on their stage of production, time of year and environmental factors.

Adult plants receive at least eight pulses of 350mm of fertigation a day. The Laubschers plan on installing solar panels in future to reduce electricity costs.

Fertiliser programmes for hydroponic cucumber production differ slightly from one farm to another, depending on the quality and pH of the water, the growth medium and climatic conditions.

“The trick with cucumber production is to find a recipe that works for you and keeps your plants happy. This means that plants should receive enough water and the right fertiliser at the right time to prevent stress,” says Laubscher.

Humidity is very low in the Vredendal area, so irrigation has to be managed with care. In some of the multi-span tunnels, water is applied through a misting system to reduce the temperature and raise humidity levels.

Although tunnel-grown cucumbers use less water than wine grapes, they are one of the highest users of water amongst tunnel-grown crops, says Laubscher.

While water is re-used in hydroponic systems in some overseas countries, the practice has not yet really taken off in South Africa.

The reason, explains Laubscher, is that it is expensive and technically too complex, as the water has to be analysed, sterilised and treated to render it suitable for re-use. Waste water is nevertheless sprayed onto the roads around the tunnels to reduce dust, which is associated with red spider mite.

He adds that many people tend to think that plants grown undercover are safer from insect pests. However, the environment that results in better growth for plants is also more favourable for insects, so problems can rapidly get out of hand if not managed in time.

According to Laubscher, one of the biggest mistakes they made on the farm was to plant in ash, as it exacerbated fusarium problems.

“We suffered huge losses because of fusarium, but have since overcome this by using plant material grafted onto pumpkin rootstock. This has since become an industry standard because of its tolerance to fungal diseases,” he explains.

Laubscher uses woodchips as the plant medium. This comprises untreated wood, as oils or chemicals from treated woodchips can interfere with the nutrients in the fertigation programme.

The grafted seedlings are bought in from Brits in North West. The Laubschers plant varieties exclusively from the Dutch company Rijk Zwaan, as these give high production volumes and are relatively disease-resistant.

They have the potential to produce between 25 and 30 cucumbers per plant in summer, and 15 and 22 in winter. The plants are used for only one season, which lasts six months.
Alzanne supplies the market all year round with gherkins and seedless / Israeli cucumbers.

“Different retailers label cucumbers by different names; one may call the same variety a seedless cucumber, while the other will call it an Israeli. This complicates on-farm packing and labelling, and also confuses consumers,” he says.

Laubscher says tunnel production may look like an easy way to make money, but it is highly scientific and requires a farmer to be hands-on.

“Small mistakes can cause big losses, so make sure you have enough knowledge and access to good support if you want to venture into this game.”

Email Nico Laubscher at [email protected].