I am running two 400W HPS on each side of my 12×6-foot room and a 1,000W HPS in the center. I am in a vertically challenged area, so a fellow grower suggested I use netting. So, I have my six ladies spread throughout the room and I have been weaving them over and under for the past three weeks, which has allowed me to spread them apart to allow inner and lower flowers light. My issue is I am unable to rotate or rearrange them, and it seems the upper foliage has grown so thick it’s not allowing the further down/bottom flowers any light. I had three 65W LED recessed lights that produce 4,000K and 650 lumens, so I mounted them six inches apart on a board and placed it approximately 12 inches away from the pots on a diagonal, pointing upwards towards my ladies, hoping to help the bottom flowers. They seem to be helping the lower flowers, but my questions are: Will it help? Will it damage anything? And is it okay that it’s white light (all the LED lights I’ve seen on your website were multiple colors, but as I said, these were here already)? — Thanks, Nicholas

By Adam Scavone | Last updated: December 15, 2021


Thank you for your question. Using trellis netting as you described is also referred to as the screen of green (ScrOG) method and is a great way to maximize the efficiency of your given light energy. When I use the ScrOG method, I also do what is called an undercut. This is usually implemented during the first few weeks of the flowering cycle when the upper portion of the plants start to fill in. An undercut consists of removing the leaves and branches that do not reach above the screen or trellis netting. In other words, remove the lower leaves and branches that will not receive adequate light. This enables the plant to focus all its energy on producing larger flowers in the upper section of the plant.

The 65W LEDs you added may help fill in the lower section a bit, but be careful when aiming light upward. The top of a plant’s leaf is designed to absorb light energy, while the bottom is not. Providing light to the underside of the leaves can cause them to twist or turn toward the light source (positive phototropism). Put another way, providing light from underneath can confuse the plant and you may end up with a crooked, misshapen plant. Your best bet would be to focus on creating a thick canopy just above the trellis netting to maximize the foliage in the light energy’s “sweet spot” (the space 12-24 inches below the light source). This may require undercutting or trimming the lower sections of the plants. The more you practice undercutting and ScrOG, the better the results will be. I hope this answers your question.

Keep on Growing,

Lee G. Lyzit

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Plant Growth Lighting Cannabis Training Techniques

Written by Adam Scavone | Compliance Director

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Adam Scavone is general counsel and compliance director for North Coast Testing Laboratories, LLC, a licensed Ohio medical marijuana testing facility, and North Coast Analytical Laboratories, LLC, an Ohio hemp testing facility.

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