The visual above shows the relation of production and light intensity. This can be converted finally into efficiency numbers calculated in gram/Mol. The visual is based on research trials (2018 to 2021) and commercial data of more than 140 data points of full growing cycles.
Choosing high performing genetics can boost your production potential up to 900+ gram/m2 dry flower weight. Most growers could reach the maximum production between 800 and 1000 PPFD. Over 1000 PPFD we experience a diminishing return on the input of light, which almost feels as a plateau on increasing production. This is exactly the point where we see that the level of crop growth steering is not easily in line any more with the intensified light level. Between 700 to 1000 PPFD the optimal climate condition can be maintained. Currently, higher PPFDs result in facilities struggling to balance climate and irrigation with their PPFD level.
Signify’s research has taught us that light use efficiency is an important metric for growers. For example, at 700 PPFD we experienced high light use efficiency, where every mol of light given was converted in 0.45g of dry flower product. From PPFD 800 to 1000, production can be maintained where the efficiency reduces from 0.42 to 0.35g/mol. After 1000 PPFD the production and efficiency decrease rapidly. To put it into perspective, each percentage of light given, with the right cultivar and climate and irrigation steering, could be providing a grower double the production when compared to the current benchmark of 500g/m2. All of that at a PPFD as low as 800-1000.
Higher light levels come with a more challenging growth process
Light, as important as it is, isn’t a cure-all and it can’t fix everything. And not only that: an over-reliance on light to the exclusion of other factors can even create environmental problems that suppress yield. Results have shown that around 1000 μmol/m2/s and beyond, the yield curve starts to diminish, because intense light creates its own complications. It may increase humidity levels due to higher transpiration of plants which often stimulate outbreaks of disease, for example. Cultivation with even higher light levels such as 1500 μmol/m2/s is like running the Olympics: if the factors are not perfect, it will cause injuries. That’s yet more testimony to the fact that growers shouldn’t put their faith exclusively in boosting grow light intensities. Rather, they should use just enough light, while also paying close attention to other factors that can affect yield. See the visual below for an overview of these factors.