Tom Lefevre satisfied with new hybrid lighting installation
Tomato grower Tom Lefevre expanded his tomato acreage under hybrid lighting from 1.5 ha to 6 ha last autumn. The first results are promising, he says. “The cultivation is more flexible because you can manage the climate more easily.”
Following installation of LEDs on 4.5 ha, Hortipower from Merksplas (Belgium) has 6 ha of hybrid lighting since last autumn. In September of last year, per segment (8 by 5 meters) two of every four SON-T lamps were replaced by two 1,000 watt lamps of the MechaTronix brand. This resulted in a light increase of 40 percent, which caused the lighting level to increase from 180 to 258 µmol/m².s. Of the total power, 90 µmol/m.s is generated by the SON-T lights. When the company is forced to switch off the SON-T lamps on warmer spring days, the LED lamps produce as much light as in the previous situation with only SON-T lamps. This is ultimately the goal of the extra LEDs: extending the lit season and generating higher yields at lower heat input and lower (energy) costs.
According to the grower, it’s still too early to make definitive calculations. “But for now it’s looking very well. The plants are stronger. The larger size of the tomatoes is particularly noticeable”, says Lefevre, who estimates the yield increase to be about 10 percent. That means the hybrid installation delivers wat he expected.
Cultivation under the higher light levels comes with a number of challenges, for instance a different irrigation strategy, he says. “That’s why we also work closely together with Proeftuin Hoogstraten and colleagues to get answers to all our questions for the coming season. “So far, we were able to keep the LED lights on the entire spring without disrupting the climate,” the grower continues. “Of course you don’t want the greenhouse to become too hot so you need to open the windows, which impacts the climate and disrupts cultivation. Because the LEDs give off less heat, you don’t suffer from that problem that much.” He adds that he consciously chooses a spectrum with white light in it. “That way, the people who look after our plants and harvest our tomatoes don’t suffer from the artificial light.”
Although the grower, in his words, still needs to learn a lot to find the right cultivation system, he notes that the first season provides a foothold. “Because the combination LED and SON-T makes it possible to play with the temperature and the amount of light, you gain a lot more flexibility in cultivation.” At this time of year the SON-T lights are only switched on when the plant doesn’t get enough light, during the darker days, or when the temperature is too low.
During a previous visit from Onder Glas, the grower already indicated that with the LEDs he can add some flexibility to his cultivation program. That way, the supply can be fine-tuned to the demand from buyers. “We’d like to be in production already by mid-November, which means you have to plant in August. This means you go into the winter season with a mature plant and you need to use one hundred percent lighting, eighteen hours a day. If you’d do that with SON-T, it would get way too hot.”
Hortipower’s clients consist of Belgian retailers. These are supplied by a group of Belgian growers under Tomeco, an organization of tomato growers linked to the auction in Hoogstraten, with a total acreage of 80 ha under glass. The grower organization specializes in all types of tomato, including San Marzano and various types of plum tomato.
Although 2020 was not a good year for conventional tomatoes, the prices decrease for specialties was not bad, Lefevre says. “It was an average year, but definitely not good. Because the hospitality sector was shut down, we had a lot of issues with the sale of slicing tomatoes.” He emphasizes that 2021 is looking a lot better in terms of pricing.
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