Think the other way around: choose your grow light before your greenhouse


Most growers who are building a new greenhouse, choose their greenhouse first. After that, they start to think about their grow light installation. Hortilux notices that often, concessions have to be made to the light plan: the crop eventually doesn’t get the ideal amount of light and also the light distribution isn’t optimal. ‘Thinking the other way around’ – choosing the grow light installation before the greenhouse – offers lots of benefits. It’s also crucial that all suppliers meet each other in an early stage.

“It often happens that we cannot optimally fill in the light of a grower because we are bound to the pattern and the dimensions of the greenhouse construction”, explains André Flinterman. He is account manager for the Netherlands and Belgium at Hortilux. “This means that you cannot, for example, always hang the fixtures in the ideal location, and concessions must therefore be made to the lighting plan. This results in the crop not getting the optimum amount of light. And that’s a shame, especially because light is crucial for crop growth. One percent more light offers one percent more revenue. The grow light installation is one of the most capital-intensive parts of the greenhouse. And this investment exceeds the investment in the greenhouse within a few years, especially if you also include the energy costs. We regularly hear from growers that they regret not having thought about their grow light installation first, and have adapted their greenhouse accordingly.” Flinterman also indicates that the importance of matching the greenhouse to the grow light installation has increased because of the increase in the number of light sources. “In the past there was only HPS, today you also have topled and interled. It is not unusual that there are three different types of light sources in one greenhouse. If you want to get the most out of this and use your grow light as efficiently as possible, that will require more of greenhouse construction. That also means that you should first think about your grow light installation and draw up a lighting plan, and only then make a choice in type of greenhouse. ”

Preach gospel

Nevertheless, most of the growers still choose the greenhouse and greenhouse construction first; only then will they start thinking about the desired grow light installation. “That is still the standard”, says Paul van der Valk, account manager for Western Europe at Hortilux. “The importance of thinking about your grow light installation in a timely manner has to get between the ears of the grower more. We see it as a gospel that must be preached.”

Hortilux’s specialists see that in some crops a change is slowly but surely going on. For example in tomato. “In tomato, eight-meter caps, with five beds of 1.60 meters were the standard,” says Flinterman. “However, the penetration of the top LEDs and the HPS light was not optimal. It was also not easy to hang up interleds. There are examples of growers who, in order to improve the light penetration, would then remove extra leaves. That is, of course, bizarre. More and more, they choose for beds of 1.72 meters, so that the possibilities of the grow light installation can be better utilized. This enables growers to achieve huge production gains. In short: in tomato, the message is slowly but surely ‘landing’. ”

Consultation between parties involved

Hortilux also advises bringing together all parties involved in the design of a greenhouse at an early stage. “There is still a lot to be gained in this area,” Van der Valk emphasizes. By bringing suppliers to the table in time, things can be optimally coordinated, and the maximum can also be achieved from the grow light installation. Flinterman illustrates this with an example. “At chrysanthemum and pot plant companies we regularly see that growers have already chosen and already installed a watering installation, and after that make choices in lighting. Consequence is that you cannot hang the luminaires in the ideal place, since the sprinkler system is already hanging here. In order to realize a good light distribution, you have to pull out all sorts of tricks. That is of course always possible, but it will be difficult to get the maximum return from your grow light installation. That is why it is wise to bring all parties together at an early stage.” Flinterman mentions in this context the advance of the “Plant Empowerment” growing method. This also requires more coordination between the various suppliers. “As a result, you see more and more airhoses in the greenhouse, which have to be at the same height as the lighting. It is important, however, that the grow light does not reflect against the hoses; otherwise, this does not reach the crop. That also requires early consultation. “