Marijuana growers are constantly trying new lighting techniques and technologies to maximize production and potency.
It isn’t always true that the more light you give cannabis plants the better they do, but when you follow the strategies in this article, you’re guaranteed to see increased cannabis plant health, yields, and potency.
The first step is to realize that top-lighting needs to be augmented by lighting that sends light onto the sides of your marijuana plants.
One reason I often put my marijuana plants outdoors is because outdoors they get light penetration not just from directly above as they get in an indoor garden, but from varying side angles.
This means that light energy directly reaches more leaves and more parts of leaves as compared to when you only have top-lighting.
In indoor marijuana grow rooms, growers often use light movers that motor-rail their lights back and forth across the ceiling.
If the HID lights on the rails have the right reflectors, the back and forth motion sends light into the plant canopy at angles different than your marijuana plants get with stationary overhead lighting.
Some cannabis growers mount their overhead stationary lights not just directly over the plant canopy but use muliple HID lights mounted at angles, and often from the corners of the grow space.
Again, this sends light deeper into the canopy for more penetration, more photosynthesis, more growth, and bigger yields.
Marijuana growers often use side lighting, especially in bloom phase.
Side lighting is most often T5 fluorescent, LED, or CFL.
Just be aware that many LED units are rip-offs that are overpriced and poorly-made.
Some of these lighting technologies don’t do so well when placed vertically, so growers often have to mount the unit horizontally on grow room walls.
This can cause spacing and safety issues in your hydroponics grow room.
Trying to use HID hydroponics lighting as side lighting isn’t practical due to heat, the potential for burn, higher electricity draw, how HID bulbs operate best in a horizontal position, and other logistical issues.
One tactic that’s useless is when people put lighting units to give bottom lighting.
Bottom lighting is light pointing upwards into the canopy from directly below.
Marijuana leaves like most plant leaves are meant to absorb light energy from the top side of the leaves, not the bottom side.
If light is sent to the bottom side of the leaves, some leaves might twist themselves up trying to reach the light. This is not good for your cannabis plants.
Another way to increase light distribution is to increase the quality and placement of reflectivity materials in your grow room.
The best materials are Mylar and dimpled aluminum, with white poly plastic a distant third.
Poor reflectivity absorbs light and doesn’t bounce it back to your marijuana plants.
Too many marijuana growers are relying on white paint, aluminum foil, and other inferior reflective materials.
Yet another tactic for getting more light penetration is to carefully and minimally trim larger leaves and useless small branches to open up your cannabis plant canopy so more light penetrates.
Further, you can use training such as LST and other strategies to make your marijuana branches grow more horizontal so there’s more exposure to light.
Because LED lighting is an increasingly popular choice for side lighting, please read this detailed article analyzing the pros and cons of LED hydroponics lighting equipment.
Up to a certain point, the more light your plants receive, the faster they grow and the bigger they yield.
Remember this, however: when you add light properly, you increase photosynthesis.
When you increase photosynthesis, you increase plant metabolism. This creates increased nutrients uptake, increased water uptake, and more evapo-transpiration.
This leads to a need for more climate control, especially to control increased humidity because your plants are sucking in and exhaling out more water.
If you have adequate top lighting via HID lights but you add 200-800 watts of side lighting in a way that visibly sends more light onto the top sides of more leaves, it’s worth it to add side lighting in your marijuana garden!