LEDs and vertical farming technology can bring significant improvements to heal grafted young plants. Greek young plant nursery AGRIS recently shared its experience with these technologies at the Grodan International Propagation Seminar.
With a production of more than 12 million grafted seedlings annually, Agris is one of the largest young plant nurseries in Southern Europe. In order to improve the quality and consistency of its production, the company started with trials 5 years ago to improve the healing stage of grafted seedlings.
Agris' production director Damianos Kintzonidis explained the harsh mediterranean climate makes it quite a challenge to produce quality grafted seedlings year round. A tomato takes six days to heal and a watermelon seven days. Within this short period of time the plants are subject to a temperature and humidity strategy that requires a very precise approach. "A very precise control of the micro climate is required."
Kintzonidis stressed that for this reason, propagators mostly use micro tunnels during the healing stage of the seedlings. "This is the traditional way, it enhances the healing, but the plants are still very susceptible to changes in climate, humidity and temperature."
Another popular method is healing in a fully closed environment with a multilayer system in which the trays with grafted seedlings can be stacked. Until now, most of the propagators used fluorescent lights in these systems. It is a more efficient production method thanks to the smaller footprint and full control of the climate. "But the drawback is that heat emitted by fluorescent lights still influence the climate too much, causing a need for additional cooling, which in turn also increases the energy costs. Therefore we researched the opportunities to install LEDs in our healing chambers", Kintzonidis explained.
Agris teamed up with the University of Thessaloniki to research the opportunities of LEDs in the healing stage. "LEDs emit less heat, are energy efficient and allow us to control the climate better. Furthermore LEDs allow you to steer the spectrum and provide the plant with a balanced mix of light to optimize the healing process and steer the morphological shape of the plant."
Agris noticed that the grafted seedlings healed under LEDs had a better overall quality. "Aside of lower energy costs and a better climate, the roots of the seedlings showed better development and the seedlings had a better overall quality as a result of less heat stress. In comparison with the propagation under fluorescent light, we experienced 2% less losses."
Kintzonidis said that Agris is currently one of the first commercial propagators who are using LEDs on such a large scale (10 healing chambers) in the healing process for the grafted plants. The production manager expects that more propagators will start with similar systems.
"Grafting and the healing process is a very critical process that requires very precise temperature, humidity and light levels. As the demand for grafted seedlings increases at a rapid pace I expect that more propagators will need to scale up their production. By using LEDs in a fully closed environment, propagators in any location and climate can achieve a consistent quality, no matter the time of the year."
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