What does it say about a technical development in greenhouse horticulture when there is a marked increase in both research projects and practical trials? What can you conclude from the surge in the number of specialist suppliers in the market? How revealing is it that growers are willing to make significant investments based on a practical trial at a colleague’s nursery?

All this tells us that the development in question is clearly very special – one that promises to boost yields and quality while at the same time cutting costs. What other explanation could there be for such a thirst for yet another exciting advance in crop cultivation?

Besides energy, plant health and water, light is the fourth hot topic for innovative, pioneering greenhouse growers. Recent research and practical trials in cut flowers, greenhouse vegetables and pot plants demonstrate the added value that diffuse light with glass, coatings or screens delivers. Artificial lighting is the other aspect to this topic, and LEDs are the most attention-grabbing innovation in this area. That’s why light takes centre stage in this issue of In Greenhouses, with the focus on innovations, research and growers’ experiences of LEDs.

It has been many years since this latest type of lighting was introduced into greenhouse horticulture. Following its much-vaunted launch, a few leading Dutch growers took the plunge, keen to make their mark as early adopters. But sometimes it’s no bad thing to wait a while. This particular development bided its time and has only made real advances in recent years. And this despite some critical noises from researchers and consultants: Have we found the right spectrum for the various crop groups? Do we have enough understanding of what light colours actually do and how they impact on plants and plant processes?
The research portfolios in several horticultural countries are crammed with LED projects in various crops. Add in the practical trials that new suppliers have initiated in the sector and you can’t help but conclude that LEDs are the future – even if there are still some key questions to be answered.

Text: Roger Abbenhuis.