Maximum Yield Canada July/August 2017
While hydroponics is unlikely to overtake traditional agriculture economically anytime soon—current US annual crop production is estimated at $143 billion while hydroponics is valued at a mere $600 million—it’s not so much as how much is being grown but where. Today, nobody knows what society will be like in 2100. We hope it will be a peaceful, healthy, and happy place.
While hydroponics is unlikely to overtake traditional agriculture economically anytime soon—current US annual crop production is estimated at $143 billion while hydroponics is valued at a mere $600 million—it’s not so much as how much is being grown but where. Today, nobody knows what society will be like in 2100. We hope it will be a peaceful, healthy, and happy place.
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leaf surface temperature<br />
OPTIMIZING GROWTH UNDER LED GROW LIGHTS<br />
When growing under LED lights with a red- and blue-dominant<br />
plant-optimized spectrum, the lack of excess infrared and<br />
other directly-usable light causes the leaves to remain cooler,<br />
meaning that ambient air temperature needs to be significantly<br />
warmer than for the same plant grown under any light<br />
(natural or artificial) that is not optimized for plant growth.<br />
LED lights utilizing primarily “white” LEDs, which are<br />
actually optimized for human eyes, are dominated by mostly<br />
yellow and green light output. This lack of plant efficiency will<br />
warm up leaves more than a red- and blue-dominant spectrum,<br />
but because they still lack the 800+ nm infrared output of most<br />
HID lights, the ambient air temperature may still need to be a<br />
little warmer to get the ideal LST.<br />
If you are switching from traditional HID lighting to LED,<br />
you can turn the temperature up a bit with white LEDs, but<br />
you need to turn it up more if you are using a plant-tuned<br />
spectrum. Not adjusting ambient air temperature to account<br />
for the spectrum change can limit your plants’ growth, and<br />
ultimately your yields.<br />
COMPARING LED GROW LIGHTS TO OTHER<br />
GROW LIGHTING TECHNOLOGIES<br />
When growing with plant-optimized LED lights, it is important<br />
to realize that ambient air temperatures need to be kept<br />
higher compared to other lighting to achieve the same<br />
metabolic rate. Side-by-side tests of LED lights versus other<br />
lighting such as HPS, where ambient air temperature is kept<br />
the same, are not particularly informative or accurate as to<br />
the lights’ relative performance—the tests should be run so<br />
that leaf surface temperature is being kept the same under<br />
each light to enable identical metabolic rates. As the data<br />
from FLIR camera observations shows, this becomes more<br />
critical especially when comparing plant-optimized LED<br />
grow lights to MH and HPS, as the leaf surface temperature<br />
difference is much higher with these lights.<br />
“NOT ADJUSTING AMBIENT air<br />
temperature to account for the spectrum<br />
change can limit your plants’ growth, and<br />
ultimately your yields.”<br />
RELATIVE ENERGY SAVINGS<br />
Heat mitigation is required in most indoor gardens using<br />
artificial lights, whether it is achieved with ventilation<br />
or air conditioning. Plant-optimized LED grow lights can<br />
offer substantial energy and cost savings in cooling.<br />
LED lights already contribute less heat to the growing<br />
environment than HPS, metal halide (MH), and fluorescent<br />
lights due to higher efficiency of light generation. Running<br />
a warmer indoor garden, as required for LED with a planttuned<br />
spectrum, can lead to a profound reduction of costs<br />
associated with cooling—not just running the cooling<br />
equipment, but also in sizing it as well.<br />
Even growing areas currently relying on excess heat<br />
from conventional grow lights can easily reduce costs<br />
with plant-optimized spectrum grow lights. In most indoor<br />
grow areas, something as simple as plastic sheeting can<br />
provide sufficient additional insulation to avoid the need<br />
for other forms of heat. In greenhouses, natural gas or<br />
propane heaters are usually much more cost-effective than<br />
relying on electric lights for heat.<br />
If growroom cooling is achieved partially or entirely through<br />
ventilation, and CO 2 supplementation is being used, the<br />
reduced need for cooling when using LED plant lights will<br />
also result in less loss of CO 2 further increasing savings.<br />
Every grower knows how important it is to keep your plants<br />
happy at the right temperature for maximum yield. LED<br />
technology allows better control of the light spectrum than<br />
ever before, and this translates into cooler leaves for your<br />
plants at the same ambient temperature. Unless you raise the<br />
air temperature with plant-optimized LED grow lights, you are<br />
keeping your plants too cool, harming your yields, and costing<br />
you more in unnecessary cooling. With non-plant-optimized<br />
“white” LEDs designed for human eyes, you may still need to<br />
raise the temperature a few degrees, but not as much as with<br />
red- and blue-dominant, plant-optimized LED grow lights.<br />
54 grow cycle