How to Set Up a Screen of Green (SCROG) Cannabis Grow
If you want to grow your own cannabis but are short on space, check out the bud-producing SCROG (screen of green) method of marijuana cultivation. Kyle Ladenburger lays out the process, step by step.
Throughout my life, one major value that’s been consistently hammered into my brain time after time is to always make the best of what you’ve got. Growing up, we were by no means poor, but money was tight enough that frivolous spending wasn’t a luxury. On most occasions we were forced to make do with what we had, as well as we could, before even considering putting money toward whatever it may be. This is something I’ve carried with me into my adult life.
This way of approaching life can be of great benefit to cannabis growers too, since space is often a limiting factor. This is true for home growers who are almost always dealing with confined indoor spaces or laws limiting the amount an individual can grow at a time. Getting the most out of each individual plant and achieving the highest potential yield possible is the key in a small cannabis garden. Many factors can contribute to reaching such goals but one method that can have a huge impact on end yields is a method called “SCROG” (screen of green).
It is ideal when growing in limited space or with limited plant numbers. This method utilizes low-stress training to allow for better overall bud development. Botanically speaking, cannabis plants exhibit a growth pattern that is referred to as apical dominance. Apical dominance is the phenomenon by which the main, central stem is the dominant growth site in comparison to lateral side shoot development. This is evident by just looking at a cannabis plant in the flowering stage. The main flower (cola) is top and center, receiving the most light and, in conjunction, more nutrients allowing it to grow larger than any other flower buds. The flowers on the sides and lower portions of the plant receive less light and develop into smaller buds commonly referred to as “larf.”
When using the SCROG method a grower will interrupt the plants’ natural apical dominance by cutting the top or main central stem off the plant. This encourages more prolific side or lateral shoot development. Instead of there being just one main cola, there will be several separate heavy flowering points on a single plant. Using a horizontal grid system, the plants will be lightly trained to grow through the grid in more of a lateral fashion compared to the normal vertical growth. The SCROG method is beneficial in several ways. It allows more light to reach the maximum number of flowering sites which will direct more available nutrients to these locations resulting in better flower production. It will also help keep the plants lower to the ground and away from the intensity and heat of powerful horticultural lighting. This can be extremely helpful when growing sativa dominant varieties that tend to stretch quite a bit during the first few weeks of flowering, especially in rooms with low ceilings. SCROG also helps the grower maintain a more uniform canopy height which comes in handy when doing regular garden maintenance. The bottom line is the SCROG method can lead to higher yields in situations where space is limited or plant counts are lower, and it can be done in just a handful of steps.
Setting Up a Screen of Green (SCROG)
The first step is to set up the grid (a.k.a. the “screen” in “screen of green”) that will be used to train the growth laterally. Wire caging will be the strongest choice, but nylon trellis netting will work as well. Just make sure it is secured tightly on all ends. Caging or trellis netting that has squares of around 2x2 inches is ideal for SCROG-ing. The grid should be placed horizontally about eight to 10 inches above the top of the pots. When growing in a tent, secure the corners of the grid tightly to the support poles on the inside corners of the tent. If the SCROG method is being used in a normal room, additional supports may be needed. In general, around one square foot of grid space should be reserved per plant.
Once the seedlings or clones reach about six to eight inches tall, where they are just about to reach the grid, the main center stem should be cut off or topped. This will encourage more side growth that will start to grow up and through the holes in the grid. Be sure that each branch has its own hole to grow through and that they are not sharing.Advertisement
This next step takes a little finesse but is relatively simple once you get the hang of it. While the plant is still in the vegetative growth stage, allow the individual branches to grow above the top of the grid by about six inches. Then begin to weave the branches down and back up through the grid. Each time the plant is tall enough above the grid repeat the weaving motion in a manner that evenly spreads the branches over the screen. You may want to use plant clips or ties to secure the branches to the grid but usually, the weaving itself will hold them in place.
One of the trickiest parts of the SCROG method is determining when to force the switch to the flowering cycle. The best way to figure this out is to understand the characteristics of the variety being grown. As stated earlier, the sativa-dominant varieties tend to stretch and grow taller during the early weeks of flowering. So, in order to not run out of grid space, they should be switched to flower earlier than an indica variety that will put on most of its growth in the vegetative stage. A general guide to follow is to allow around 50-60 percent of the grid to be covered before switching to flowering cycle for sativa. For an indica variety, allow as much as 70-80 percent coverage before forcing into flowering cycle.Advertisement
While the plant grows and the branches are continually weaved through the grid, the bottom portion of the plant should be given attention as well. As the grid fills up, the amount of light that can penetrate past it is diminished; this is really the whole point of the SCROG method. Any vegetative growth, such as fan leaves and branches, growing under will not receive enough light for any substantial growth and should be removed on a regular basis. Keeping the plants bare beneath the canopy will also make regular feeding/watering and maintenance a much easier task. Continue to keep the bottom branches clear as the flowers continue to grow and a nice harvest should follow.
When it comes to growing cannabis indoors, limited space does not always have to mean smaller yields. The SCROG method and other similar techniques are a relatively easy way to create more highly active flower bud sites with increased developmental potential. Putting in the small amount of work involved will almost always be worth it and it’s a great way to make the most with what you have.
Written by Kyle Ladenburger | Director of Regulatory Affairs for Age Old Organics & ENP Turf, Freelance Garden Writer