Hydroponics lighting is so vital for your marijuana plants, but there’s so much misinformation and confusing information. Even those of us who spend all our time studying hydroponics equipment have a hard time sorting all the claims and technology.
One thing I like to do is talk to pros who sell hydroponics HID, digital ballasts, magnetic core and coil ballasts, LED units, T-5 hydroponics lighting and other gear, and see what they say. Some hydroponics retailers don’t know shit about your marijuana crops, or won’t admit to it. Others are merely gonna sell you the hydroponics lighting that makes them the most profits.
But I’m fortunate to know hydroponics retailers that go the extra mile in product testing and customer care. They listen to hydroponics growers, and they test hydroponics lighting gear. That’s how they learn the good and bad about hydroponics lighting products. Then they tell me what they’ve learned. I write it all down so you can find the hydroponics lighting that gives you the most THC per watt.
One store I talk to has a ballast, bulb and hood testing station where customers bring in used lighting equipment to see how well it’s performing. They use meters that measure Photosynthetically Active Radiation (PAR) as well as total light intensity (lumens per square meter).
PAR is the new buzzword for those of us trying to grow the marijuana that gives us the biggest buzz. It comes from the concept of light as “nutrition.” Remember that only a narrow set of wavelengths provide your marijuana plants the light they most want so they can hit maximum photosynthesis. Specific light wavelengths trigger your plants to produce bigger buds and more THC.
You already utilize the differences in how light wavelengths affect plant growth when you utilize bluish Metal Halide HID lighting during grow phase and switch to “orange-colored” light via High Pressure Sodium (HPS) HID during bloom phase.
When people use meters to measure PAR, or when hydroponics lighting manufacturers tune their lights to produce the ideal PAR spectrum for marijuana, that’s a sign that the hydroponics lighting industry is changing for the better.
Most serious marijuana growers use light meters in their grow rooms. These meters read light visible to the human eye and give a simple lux or lumens measurement that tells us how much generic radiation our hydroponics lighting is producing. Growers use them to find low-light areas.
The problem with using those generic meters is they do not measure PAR. The latest trend in hydroponics lighting measurement is to use PAR meters. They’re also called “quantum meters.” Not the brand “Quantum.” They measure light wavelengths only between 400-700 nanomoles (nm). Why? Because within that range are the only light wavelengths your marijuana plants consume to fuel photosynthesis and other functions.
Please note that ultraviolet (UV) light (you can’t see it, but it can burn your skin even on a cloudy day) is said to affect marijuana plants. One type, UVB, is alleged to increase resin gland production, although there hasn’t been the kind of for sure proof that would convince me to add UVB lighting to my grow op.
PAR meters report PAR as units of micromoles per square meter per second (µmol·m²·sec). Full sunlight at noon measured with a PAR meter gives you a reading around 2,000 µmol·m²·sec. If you have modernized hydroponics lighting equipment and position it properly in your hydroponics grow room so that you optimize coverage and light penetration, you provide your marijuana almost as much PAR as you’d get from the sun!
Combined with an aggressive feed program (1200 ppm or higher), extra grow room C02 and other inputs, intense indoor PAR gives you much heavier harvests and more THC.
The wavelengths your marijuana plants most need are in two very specific narrow ranges within the 400-700nm spectrum. One of these is around 420-450nm, in the blue end of the visible spectrum. This would most correspond with your Metal Halide HID hydroponics lighting bulb or T-5 fluorescents, although few HID bulbs or T-5 units are specifically and correctly engineered with photosynthesis in mind. The good news is that some hydroponics lighting manufacturers have paid attention to your needs as a marijuana grower- so now you get HID bulbs enginered to grow you bigger, better buds!
Hydroponics lighting that produces light in the bluish end of the spectrum is used for grow phase. In bloom phase, we switch to lighting with more red in it because that’s what marijuana plants have evolved to most use to make floral structures and resins such as THC. That type of light is in the 630-700nm wavelength range. To your eyes, that light appears mostly as red.
Probably you are realizing that hydroponics lighting and light are similar to hydroponics nutrients. In grow phase you feed grow base nutrients that are heavy on nitrogen. In bloom phase you feed bloom base nutrients and bloom boosters that are lighter on nitrogen and heavier on potassium and phosphorus.
Similarly, in grow phase you go to Metal Halide, and then in bloom phase you switch to High Pressure Sodium. You go from a mostly-bluish light to mostly-red light, because your marijuana plants need different things at different times, just as with the nutrition that comes to them via their roots.
In our next article in this series we will further explore hydroponics lighting for marijuana. As you can see, it isn’t as simple as some would have had you believe. But thanks to pioneering and grower-oriented hydroponics researchers, manufacturers and retailers (such as Miramar Hydroponics who helped with this article), we are finally starting to see hydroponics lighting technology maximized for marijuana weight and THC. You get more bud and more THC per watt when you use this information to upgrade your hydroponics lighting strategies, so stay tuned to Big Buds for more hydroponics lighting news you can use.