With marijuana becoming legal across Canada, the interest and need for effective and efficient growing options are in high demand. Many provinces now allow people to grow their cannabis, yet at the same time, they often restrict the number of plants that each individual or household can grow.
This creates a bottleneck, whereby personal need exceeds production. Finding a way to maximize your yield with a limited number of plants and limited space has become one of the largest challenges for a modern cannabis grower. This is where SCROG comes in.
SCROG stands for “Screen of Green“. It is a simple method for cultivating cannabis plants that require little space and little maintenance, yet can increase yields by up to 30% or more. While the method itself is simple, the preparation and attention to detail are critical for a good harvest.
What this method does is creates a canopy of leaves where the buds can grow and mature together at the same height. This reduces the need to cultivate on multiple levels, where light levels can be inconsistent as they filter down through higher leaves.
This increases light absorption by the producing portions of the plant, and as it is horizontal rather than vertical, it allows for a single large plant to receive the same light and nutrients to every flower. What you end up with is a flat canopy of beautiful well-formed healthy buds, with little to no wasted space or unproductive stems.
Simply put, properly creating your Screen of Green ensures that you get the most product out of each plant. With even a single plant and careful training, the SCROG method can yield a greater volume of product than traditional vertical cultivation methods.
Also, since it is a more efficient use of space, it requires less square footage and fewer lamps. With all of the growing portions of the plant receiving the same amount of light consistently, there are no secondary leaves below the canopy leaching nutrients from the growing process.
The best time to use the SCROG method of marijuana cultivation is when space is limited, there are limited light sources, or there are simply a limited number of plants that can be grown legally. Arguably, however, it is an effective method for increasing crop yield any time it is used.
It is highly effective indoors but can also be used outdoors in a greenhouse setting with many advantages. With limited lighting fixtures and height requirements, the SCROG method allows cultivators to maximize the exposure of light and nutrients to producing portions of plants. It does this by laying out the leaves and buds in a horizontal manner across a wire or mesh screen rather than through conventional vertical growing.
Let’s take a look at how to accomplish this.
To ensure success with the SCROG method of cannabis cultivation, careful attention to detail is required. This method is simple enough to do almost anywhere, with very limited resources, but it needs to be done correctly. Here’s what you will need to do.
The SCROG method works incredibly well for both soil-based and hydroponic growth. When you are setting up your grow room, it is important to decide early on which method you’re going to use. Since this cultivation and training method works well with both, this article is going to gloss over soil preparation or water delivery methods.
To maximize space and manage light resources more exactly, we suggest using a grow tent, at least 3×3 feet. This is big enough for four plants to grow comfortably and small enough to only require one light fixture.
Besides which strain you are cultivating, your choice in lights is probably the most important factor in your success as a grower. Regardless of which method you used to cultivate your plants, marijuana cultivation can be broken down into two distinct stages.
Traditionally these two stages were differentiated by using two different types of light. Typically the vegetative stage has been accomplished by using Metal Halide (MH) bulbs of at least 400w to induce growth and provide a high-intensity discharge of light and heat for the growing plants. In contrast, for the flowering stage, High-Pressure Sodium (HPS) lights provide the right spectrum of visible and non-visible light to encourage the plants to bloom rapidly. These also need to be at least 400w.
But switching back and forth between these two forms of light can be troublesome, not to mention costly. Factoring in electrical cost for running these high output lights has traditionally made this lighting method inefficient and expensive.
Many modern growers, however, are switching to full-spectrum LED lights, allowing them to change what type and amount of light are being absorbed by their plants at each stage of the growth cycle. Lighting systems like the AI GrowLight even allow for full functionality to be programmed through a linked smart device. And as the online community of growers continues to expand, “light recipes” for different strains and set-ups become an increasingly shared community experience.
A final note on lighting – different types of light needs to be hung at different heights above the plants. Be careful to research the optimal distance between the fixtures and plants before hanging the lights once you decide which type of lamps to use, or you run the risk of damaging your crops.
As your plants mature, cannabis begins to produce a very pungent and aromatic smell. Many growers find it important to ventilate their grow room with an extractor combined with an effective carbon filter to neutralize the smell. It is also important that the plants have a fresh and steady supply of CO2 for optimal health. Growing inside of a tent, oxygen levels can get to a hazardous level for cannabis plants.
For a 3×3 foot tent, we recommend a ventilation system that can move approximately 9,000 to 10,000 cubic feet of air with a carbon filter that matches that volume. Take the time to invest in proper ventilation if using an enclosed growing method.
In as much as you want the right lights for your cultivation, you most assuredly want the right plants. We suggest either growing seedlings from seeds provided by a certified source of feminized seeds, or from cuttings made from a healthy female mother plant.
Growing random seeds has a chance of producing male plants, which can ruin an entire crop if they fertilize the females. It is also difficult to identify male or female plants until after they reach sexual maturity, and by that time you’ve invested a large amount of time and effort, not to mention resources. Take the guesswork and risk out of the equation by starting with only female plants.
Begin with healthy stock, and you will end with healthy buds.
The SCROG process truly starts when the plants have reached 10 inches in height. You will want to move them from your seedling or clone box into the grow room at this point.
Inside your grow room you will want to place your screen at 20 to 24 inches above the top of the pots. The screen can be almost any kind of material but needs at least 2×2 inch holes to thread the growing stems through. You will also need to secure the stems horizontally to the screen several times so that it forms a thick layer of green leaves, so make sure it’s sturdy.
As noted above, make sure there is adequate space above the screen for your lighting fixtures. The buds will grow above the screen, so review your distance and leave yourself adequate space between your fixture and your plants.
Once your plants have reached about 10 inches in height and they are securely under the grow lights and screen, you’ll want to start the training process. Left to their ends, cannabis plants grow tall and bushy. The SCROG method forces them to branch out lower and focuses that growth to a limited number of strong woven branches. Here’s how.
Using a pair of sterilized pruning scissors, begin by cutting off the top cola of each plant. This forces the plant to grow more side branches and shoots lower down the plant. You want the branches to reach the screen at roughly the same time, so once the top of your plant reaches the bottom of the screen you’ll want to move on to the next step.
It is now time to choose your champions. Select the branches that are growing tallest and healthiest, closest to the screen. Prune off all of the other bottom branches and side shoots when the top hits the screen. This forces nutrients to only go to the areas of growth and production. Your plant will see rapid growth after this stage.
Two days after pruning out the bottom branches and shoots, it is now time to switch the light cycle over to the flowering stage. Do this by switching your light exposure over to a 12-hour cycle. By creating an equal “day” and “night” exposure for the plants, it tricks them into thinking that there is a change of season occurring. This forces them to begin to flower.
Be careful, however. Resist the urge to check on your plants during their “night” cycle. Even a small amount of light can disrupt them, shocking them back into a growth cycle. Not only can this disrupt your harvest time, but it creates unhealthy stress on the plants that they may not recover from. Treat them gently during this stage and let them rest.
Once you have switched over to a flowering light cycle, it is now time to begin carefully monitoring the growth of your plants. With the excess branches and shoots removed, the selected growing limbs will start moving upward rapidly. Now is the time to start carefully moving them into position on the screen.
Be very careful as you attach your branches. They are supple but any breakage can disrupt the growth and cause the plant to send valuable nutrients and moisture to the wound site rather than to the growing buds. Attaching the branches to the wire screen by tying them in place and tucking them into adjacent holes as they grow.
As each branch pops through the screen, keep them in separate holes so each branch has adequate room to grow. Tuck and weave them through the neighboring holes in the screen to create a canopy of green with each plant. As the flowers start to form and mature, this training will keep them adequately spaced and allow even distribution of all the light, maximizing your yield when it comes time to harvest.
Growing isn’t always easy, but when it’s done right it can be one of the most rewarding experiences we can undertake. Take the time to familiarize yourself with every aspect of the process. Get to know your strains and equipment. Invest the time and energy in researching the right equipment and get involved with the growing community of cultivators that are emerging.
Marijuana cultivation is no longer something done in secret. The resources and sense of community available to modern growers are like nothing we’ve ever experienced. Use it. Get involved and listen to the people that are growing and enjoying their product. Share your own stories and observations, because you are a valuable member of that community as well.
Growing gives us more than an amazing product. It gives us a voice and a sense of community like never before. Don’t be afraid to be the one that benefits from growing this diverse plant! Check out i49.net for seeds and growing tips!