Tomato growers soon starts:
100% LEDs on a commercial acreage of 1.7 hectares
The news was shared last month at the knowledge cafe LED and at DLV / GreenQ in the Improvement Centre. In an ongoing experiment at the Centre, various companies are testing the ability of 100% LED lighting in tomatoes. The greenhouse offers µmol/(m².s) LED top lighting and 53 µmol/(m².s) LED inter lighting by Philips. Koppert is trialing the Natugro concept and residue-free cultivation, while Grodan is testing a new irrigation strategy and De Ruiter has several varieties under the lamps. The overall aim is to see whether or not the production can be boosted to more than 95 kg / m2. Willem Valstar of StarGrow Consultancy oversees the trial.
Further research
The trial is a continuation of last year's survey, in which three lighting strategies were tested. Komeett is now top grafted on Maxifort instead of 1 on 1. The planting date was brought forward on October 9 and cultivation is now done on a slab of ten centimeters instead of seven. Also, Vertifans were installed this year. Production is currently at 50.6 kg - significantly higher than the 38,5 kg harvested by this time last year. But that also has to do with the earlier planting date, as is shown by Piet Hein van Baar of DLV GreenQ in several graphs. Still, final production estimate is higher than last year’s: presently at 97.6 kg.
Experiences
During the test, the LED lighting from Philips plays an important role, as a large portion of the trial revolves around the behavior of the plants under 100% LED. Based on several studies, Esther van Echtelt concludes that cultivation with 100% LED is perfectly feasibly. "But you have to take into account other principles than with traditional lighting," she says.
The low-heat and energy-efficient LED lighting achieves a more even climate and makes an earlier planting time possible, as well as a longer lighting period. In winter, more screening and less venting allows for crops to stay fresh and vital throughout the season. But that is also something growers must keep in mind: less heat in the top. "Your temperature should be higher to realize sufficient flowering speed. With plant density you need to go for fruit production instead of vine formation. That’s a new way of thinking," says Van Echtelt. Van Baar confirms this: "Growing is efficient under LED, but vine production is just slightly lower than with Son-T. Adjust your planting density to achieve the desired fruit production."
Investment
Despite the results of the investigations and the enthusiasm of both participating parties and the supervisors, skepticism still prevails among growers, at least according to the debate. Not so much in regard to LED lighting, but in relation to the investments required. For example, growers fear that the efficiency of LEDs will increase so rapidly in coming years, that an investment now will quickly lose profitability as current units get outdated. According to Van Echtelt, who led the debate, that fear is unjustified. "Not only because it’s impossible to predict how fast this development continues, but also because your LED investment is part of a larger plan in which you look at increased production and sales in the long run. The efficiency of LED is therefore part out of your profitability, and can differ per grower and situation. We can help growers with these considerations."
More information:
StarGrow Consultancy
Willem Valstar
T: 0031(6)-50516100
E: willem@stargrowconsultancy.nl
www.greenhousecropconsultants.com/?1=willem-valstar
Daniela Damoiseaux
Global Marcom Manager Horticulture
Philips Horticultural Lighting, Nederland
Tel.: +31 (0)6 316 5 2696
E-mail: daniela.damoiseaux@philips.com
www.philips.com/horti
More information:
DLV GreenQ
www.dlvplant.nl
www.greenq.nl