We reached out to Dr. David Hawley, Principal Scientist at Fluence, for more insights on how commercial growers can apply lessons from the research to their own operations.
Greenhouse Grower (GG): How can this research help growers make informed lighting decisions?
David Hawley: When growers talk with us, and they say want the best light for their crops, that doesn’t mean much. We ask what they want to achieve. What’s best for you may not be best for your neighbor. It varies by crop. Most growers in vine crops, for example have the goal of yield of fresh mass. That is different than someone growing for dry mass. Conversely in cannabis, they care about yield, but their top priority is chemistry or plant quality. If we have a solution for them that can get high yields, but the chemistry is poor, or the THC is low, that’s not the right light for them. They need something to get both quality and yield.
GG: How can growers take this research and develop their own programs?
Hawley: We know the fundemental research we do is smaller than commercial scale and growers may feel concerned our results might not apply to their facility. We try to translate our research results to the commercial scale through commercial grower trials. We have a Horticultural Services team, and they will deploy trials or case studies and apply research trial treatments to a commercial facility so they can see how it can be applicable to them. We also design every research trial so that it is as commercially relevant as possible. From density to temperature to humidity to training of plants for any crop, all of that is designed at the research level first, then through the Horticultural Services team, as well as sometimes through growers from Europe who will review the research and tell us what makes sense. We’ll also bring growers along for the ride through research field days. They help us maintain the study in a way that is commercially relevant, which also helps us communicate results.
GG: Was the cannabis lighting research done in a greenhouse or indoor facility, and what are the differences?
Hawley: The study referenced in our initial announcement was done in an indoor environment, but we have other greenhouse-based research. The greenhouse lighting research we’ve done was with lower PPFDs than we’d recommend for growers that have the electrical capacity to go with higher PPFDs. We were power restricted, but it was still an interesting study because a lot of other growers are also power limited. If they have to increase their light (switching from tomatoes to cannabis, for example), adding electrical capacity can be daunting.
This coming greenhouse season, we are also looking at light spectra at 1,000 micromoles, and expanding the library of different cannabis cultivars we’ve studied in greenhouses.
GG: How can research like this convince growers to shift to LEDs?
Hawley: The bottom line is profitability. Regardless of the market and how they feel about how LEDs affect plants, all the data from us and elsewhere shows that LEDs are more efficacious than high-pressure sodium systems. You’ll get at least as good productivity, and it’s better for profitability once you overcome the initial capital investment. That capital investment is also easier to overcome than many expect due to rebate programs. At the end of the day, that bottom line profitability is really hard to argue with.