Every cucumber grower has his own strategy for achieving the best yield. Frank van Lipzig wants to grow sustainably, achieve a high quality as well as harvest lots of fruits. He is now in his second season of high wire production. Last year was a transition year but now he has developed a clear strategy to keep the crop in balance.
This year Frank van Lipzig has been able to sell his cucumbers with an environmentally friendly quality mark. This is because his nursery has a good water source, supplied by a well and rainwater, and because he knows exactly what and how much residual water he drains off. The cucumbers on his 8.5 ha nursery in the ‘California’ horticultural area in Limburg in the south east of the Netherlands, look in good shape.
Last year he switched from a strategy of two cucumber crops and one tomato crop per year to two crops of cucumbers on high wires. For him it was a year of new concepts. “I decided to stop with the autumn crop due to the lack of profit from the CHP cogenerator. I also noticed that tomato growers with artificial lighting were catching me up on quality. With the high wire crop the costs per fruit are lower, I can deliver a better and more consistent quality and I have a better overview of the labour and organisation. All the different aspects just came together,” explains the good-humoured Limburger, occasionally taking a bite from a young cucumber.
Van Lipzig is very careful about water usage. Bearing in mind he wants to have the most sustainable approach possible he has also adapted his watering strategy. By perfecting the watering he wants to be able to control his crop as much as possible. “My ambition is to bring the quality to an even higher level,” he says.
Frank Janssen, of substrate supplier Grodan, advises the nursery about the choice of slab. Janssen: “Each grower has his own way of cultivation. The art is to match the slab with his type of plant, watering strategy and crop.”
Since 2008 the nursery has been using a 10 cm high Grotop Expert slab that lends itself to ‘Precision Growing’. His colleague, Kees Struijk, explains the concept. “It is one of our strategic decisions. It is absolutely necessary worldwide to deal sensibly with water and fertilisers because less and less is becoming available. Therefore it is a challenge for growers to achieve the maximum results with less inputs.”
Struijk has noticed a growing interest in this subject. Ten years ago the focus was completely on the climate; now controlling the crop is much more linked to energy use, choice of variety, water use and root quality.
Janssen: “We have two slabs available for cucumbers; one has a more open structure (Vital) and can be watered continuously and frequently. The other has a more closed structure, which makes it possible to have a higher desaturation capacity. Every grower has his own preference.”
Van Lipzig choose the somewhat tighter fibre structure because then he can better apply his own watering strategy. The slab has a wide control range. The water content can vary between 50 and 80% without it harming growth vigour. A Plantop Delta stonewool block, with homogenous water distribution, is placed on top of this slab. He thought for a long time about the choice of slab but left the choice of stonewool block to his plant supplier. “Everyone has their profession,” he says.
In the greenhouse the slabs are placed directly on the ground film. The dripper system in the 150 metre long path is simple. The grower uses normal labyrinth drippers and a nutrient solution is sent from both ends into the dripper hose. “I maintain good control with this combination. In principle I don’t need to water at night. During the day I can water as often I think is necessary.” During the winter that could be just one watering per 24 hours, while in the summer it’s almost continuous depending on the radiation. He doesn’t lower the EC because due to the watering strategy that’s not necessary. This remains constantly at 2.8.
Transition to high wire
“I began with this taller slab because I had a new greenhouse and therefore I expected generative crop growth,” explains the cucumber grower. In the meantime he knows everything from A to Z about the cultivating system and sees no reason to change. He has always prepared the fertiliser containers and done the watering himself simply because he enjoys it and he finds it interesting. He also gets feedback from his crop advisor. He is able to steer the crop based on a strategy of not providing any water at night and allowing the slab to dry out.
When he switched to the high wire production this strategy hardly changed. However, he did notice that cultivating a crop for longer requires a different approach to cultivating three short crops after each other. Growing a crop for a shorter period requires more attention to certain phases of the plant while a longer crop requires continuity.
And so he started cautiously, but nevertheless enthusiastically, with the first high wire crop. In week 9 he maintained an extra top and in so doing went from 1.5 to 3 stems per m2. “Due to this there was a real peak in plant burden which resulted in the fruits remaining on the plant for too long,” he says.
Based on this experience Van Lipzig began this season differently. This time he maintained extra tops at an earlier stage but did it in phases. In week 8 he went from 1.5 to 2.25 stems per m2 and in week 11 from 2.25 to 3 stems per m2. This suits him much better.
The grower puts all his energy into maintaining a balance in the crop, because he believes peak burdens are not the way to obtain maximum yield. “The art of growing cucumbers on a high wire is to obtain and maintain a balance in the crop.”
Cucumber grower Frank van Lipzig purposefully decided to use a stonewool slab with a tighter structure and large volume. He doesn’t irrigate at night and so allows the water volume in the slab to dry out. By using this strategy he can keep the high wire crop well balanced and achieve better utilisation of water and fertilisers.
Text/photos: Pieternel van Velden