This post focuses on how Printed LED Boards became the most efficient method of growing cannabis. You may have noticed the LED on your smartphone has gotten much brighter over the last 10 years. The same improvements in LED technology have revolutionized indoor growing.

The first LED grow lights were Blue/Purple LED grow lights you see all over Amazon. They are commonly sold under Mars Hydro, Viparspectra, and Philzon branding including many other. Internal components are the same, you can get factories in China to engrave whatever name you want on the box. Just don’t put the Grow Doctor’s name on this obsolete junk.

These lights are less efficient than White LEDs and produce an unsightly “blurple” color in your grow room. This makes it difficult to diagnose plants and enjoy the company of your ladies. Most of these blurple lights also have LED’s in the UV spectrum (10-400nm) which lies outside the absorption range for Clorophyll A & B ( 400-700nm).

In other words, do not buy blue/purple lights for your grow. They are being phased out and will be obsolete in a number of years.

Surface Mounted Devices (SMD) – SMD’s have only one diode per chip, making them much less efficient than COB LED’s which can have 9 diodes or more per chip. The transition from SMD to COB LED’s is most apparent around 2013-2014 when cell phone flashlights started getting really bright. SMD’s have the advantage of being able to change color at the expense of being less efficient

SMD5050 represents a 5mm wide LED while SMD3528 is a 3.5mm LED. SMD’s are still useful in light strip applications to supplements COB lighting.

The main difference between SMD and COB LED is the number of diodes. Much like advancements in microprocessors, our ability to pack more diodes in a small space led to greater efficiencies at a reduced size.

‘Growmau5’ was the first to start using CREE COB LED’s to grow cannabis. He rose to fame among online grow communities with a series of DIY youtube videos showing yields exceeding 2 grams/watt. With traditional HPS lights, you were a master grower if you could achieve 1 gram/watt.

The growmau5 style involved using massive single COB LED drawing 50-100 watts per chip. The light is spread out from this single point using a 90-degree lens. The lens is mounted to a heatsink which has a small MeanWell driver above it regulating current and providing the required voltage.

The issue with these CREE COB’s is higher cost and less effective light dispersion. Some claim that the greater intensity penetrates the canopy further but this theory is not supported by my experience.

Where is Growmau5 now? He partnered with RapidLED and started a line of ChilledLogic LED fixtures. The ‘pucks’ on his new lights resemble mini printed LED boards. Instead of one large COB LED they have dozens of chips on a round board. It is a nice design which looks clean. They also have even light dispersion like a square LED board. You can see that even Growmau5 himself has moved away from using single high power chips in the 50-100 watt range. The heat with these mega chips is too concentrated and needs to be spread out over a wider surface.

Printed LED Boards – are the solution to heat issues/light dispersion problems that high power (50-100 watt) chips face. These LED boards were first branded by the company HorticultureLightingGroup or HLG. They decided to call them Quantum Boards and many still use this name to refer to Printed LED boards powered by Meanwell drivers. Their advantages are two-fold. The boards provide more even light/heat distribution to your canopy. They are also more cost-effective when using the doctors favorite metric: PPFD/$. For example, a 100-watt single chip CREE will run you approx $100 while a 240-Watt Printed LED board can be had for $140.

Alibaba boards use the same Meanwell HLG driver that Horticulture Lighting uses. The Doc suspects that Horticulture Lighting Group named themselves HLG to coincide with the name of the Taiwanese made Meanwell HLG driver that powers the board, causing confusion in the marketplace.