[Growers] Q&A

Great question. Unfortunately the answer is it depends.. So let's split your questions..First I think you are asking how much can increase my yield by adding under canopy lights. The answer there is It depends. Cannabis and Hemp can handle high intensity light better than most plants. Dr. Bruce Bugbee and his research team at the USU Plant Physiology department determine they could handle up to 2000 PPFD prior to shutting down (when photosynthesis stops) but that level of intensity varies significantly by strain and cultivar. Additional factors also need to be considered for example CO2 and 02 at the substrate. Both of which improve nutrient uptake and transpiration / growth rate. Typically in commercial facility design we build living soil facilities somewhere between 800 and 900 PPFD. Organic nutrients take longer to get started and typically take longer to finish. As nutrient breakdown is critical for growth, to accelerate growth most facilities use salt based nutrients. Salt base nutrients of absorbed much easier that organic by the plants so for facilities that are salt based nutrients we design for between 1,000 and 1600 PPFD as Dr Bugbee proved there's a linear relationship between PPFD and harvested weight. You increase your blood intensity by 10% get 10% more yield. Proportional.. now you have to factor in HVAC capacity dehumidification capacity watering interval and efficiency etc. FC commercial facilities running efficiently with 1,400 PPFD. But those facilities are invested in environmental monitoring software environmental management software, nano bubble generators CO2 generators etc.. They built a safety net of systems that allowed to run at that intensity.. That approach is certainly not in an expensive one..

If under canopy lighting give you proportional yield increases as adding more intensity overhead, Did any more intensity overhead would be your least expensive option. If you're going to invest it under canopy lighting you want a return that's greater than that. And that depends on which light you have overhead. Our high bay lights at Scynce have patented optics That increase photon delivery efficacy, something called a coefficient of utilization or CU which measures the percentage of photons delivered to the canopy so that the leakage percentage can also be determined which is the amount of photons produced at the diode that are wasted and never reach the canopy. Because of the improved CU, clients grow 6' tall plants under our lights and do not lollipop or prune the bottoms of the plants.. Due to the CU we are able to harden and finish even the lower level buds, so adding under canopy light that says the same effect as adding light overhead..

Other lighting manufacturers opt for no optics and for them the optimal light at its highest intensity gives them good penetration up to 24 in. Into the canopy, And then intensively declines exponentially. To avoid large cultivators prune or lollipop their plants. In this case adding under canopy light will have more than an incremental benefit and therefore it's a lot more cost justified.

But also consider a factor in the fact that under canopy lighting will produce heat and depending on how much wattage you're throwing from the bottom it's going to produce that heat and the worst possible place under the canopy and one hot air rises it's going to settle in your canopy while at the same time plants transpiring are going to expel oxygen-rich moisture-rich air into the canopy.. And wall mounted fans rarely do a decent job of actually penetrating that canopy with fresh air... If you're going to have a mold or a bug infestation more often than not the originating location of that infestation is your canopy which is also where all of your valuable product is...

Before installing under canopy lights Ensure your HVAC and your dehumidification regiment can handle the added heat load.. And consider a trau replacement like the Dual draft system that allows you to deliver fresh CO2 enriched air from under the canopy forcing the added heat and the transpired moisture up and out of the canopy..

Last part of the question I'm going to give a brief answer but it's worth further discussion. Does the under canopy need to match the over canopy and he answers absolutely not. Under canopy light can be used to augment spectrum and crop steer. So if you purchase six spectrum over top lights, One way to take advantage of cryptochrome photochrom activation, The Emerson effect, manipulate plant morphology, etc. is by mixing the spectrum from above and below to the rent ratios to have the desired effect. And every overhead light is a little different spectrum wise, which is why companies like Faven who focus on under canopy solutions, are releasing dynamic spectrum tunable under canopy fixtures.. an additional factor to consider is that certain color photons permeate leaf material better than others red and far red in particular can actually be applied through leaf material so in a lot of ways It makes sense to have under canopy lights the focus on those two spectrums.. which works great if you have a full spectrum white blue heavy light over the top..

What ratio spectrums above or below work together well... No one knows for sure as under canopy lighting is still fairly new and little testing has been done to validate these types of ratios which is further complicated by the fact that every strain and every cultivar of that strain are going to respond to spectrum just a little bit differently. More research is certainly needed in this area....

Sorry for the novel but you buried five questions into one.. DM me if you have additional questions..