If you’ve heard of the term SCROG, you probably want to try it, but what if you don’t know what to do?
I am here to help. This article will explain when and how to SCROG so that you can take advantage of this powerful growing technique.
I’ll also share a photo guide for those that prefer pictures over words, and a shopping list so that you have everything that you need. If you have any questions about scrogging, I intend to answer them below.
Keep reading or skip ahead to your favorite part:
What is scrogging?
If you know any marijuana growers, you have probably heard the term “SCROG” before. Much like many growing techniques, scrogging marijuana strives to make the process a little bit easier and a lot more beneficial.
What does it mean?
The term “SCROG” is an abbreviation for “Screen of Green.”
What is that?
Screen of Green is a method that optimizes your lights by bringing lower buds up to the top of the canopy.
This is useful because:
Better light distribution helps produce higher yields!
The scrogging method has been around for a while. People have been using it since before high-intensity discharge—HID—lamps. It can improve the yield of your grow, even with basic fluorescent lights.
Don’t want to read? Watch the video!
Marijuana growers are always looking for the next best way to get their plants to grow the most efficiently. High yields, potent buds, and bushy plants make the world go ‘round for growers. Scrogging helps your plants grow bushier and use up their space more efficiently.
To be specific:
Scrogging is a type of training for marijuana plants that involves securing a screen above the canopy of your plants, and then tying the growth from the plants onto the screen as time goes on.
Tip: make sure to download my free Grow Bible for more advanced growing techniques
It’s typically not done alone, however.
Proper scrogging works best if you also use other methods, such as topping. Topping basically involves cutting off the tops of your marijuana plants, so they grow outwards rather than upwards. This helps them grow more branches and become bushier, while scrogging helps every part of those branches and leaves to get exposed to sunlight, making for an extremely efficient use of space.
Who should SCROG?
Wondering if you should bother with this technique?
If you intend to only grow a few plants, yes.
Scrogging is perfect for people who live in a state where growing marijuana is legal, but only in small amounts. For example, several states in the US let you grow five plants or less.
If you are trying to get as much weed out of your garden as possible, five plants aren’t that many. Scrogging lets you get the most “bang for your buck” when you must grow in limited numbers.
Small-scale gardeners aren’t the only ones who benefit.
Scrogging is especially useful for those who want to grow large Sativas in a smaller space. It lets them manipulate the growth until every bit of light is hitting the plants somewhere, rather than being wasted by hitting the floor instead.
Shopping list for a successful SCROG
It’s important to know what your entire grow room needs before you even think about scrogging. For the grow room part, the following items are an example of what you could use:
- 1 x 3×3 foot tent
- 1 x 400 watt MH during vegetative stage
- 1 x 400-watt HPS during flowering stage
- 1 x 9,000 feet cubed extractor
- 1 x 10,500 feet cubed filter
- 1 x 3,500 feet cubed inlet
- 4 x 6.5-gallon pot
- 4 x Amnesia cuttings
- Flower Power nutrients
Tip: read my article How to Build a Grow Room for more information
In terms of equipment for the actual act of scrogging, you will simply need a screen, scissors, and some large pots. Let’s look at some of the details behind each of these.
This is the most obvious (and perhaps the most important) piece of equipment needed for scrogging. The actual screen is not as important as how you use it, however. Keep in mind that you will just need to be able to tie the branches of your marijuana plants to it several times. It will eventually create a blanket of leaves and buds all at the exact same height.
Although any sharp scissors will do, you shouldn’t just pick up scissors from your office and start using that. Instead, make sure it is very sharp, then clean and sterilize it before using it on your plants. Much like you would be careful around a wound on a person to prevent infection, the same precautions are necessary on the “wounds” you will make on your marijuana plants.
Assuming you won’t have a large number of plants to grow (since scrogging is usually used by people who can only grow a limited number of marijuana plants), large pots are the way to go. Larger pots will allow the yield to be maximized as much as possible when you are using the scrogging technique.
Installing your screen of green
Just as important as what you buy is how you decide to use it. Some of these steps may seem painfully obvious, but you would be surprised.
Trust us: it’s better to be clear. Check out these photo series by Bergmanslab.com
First of all, fill the large pots with soil after placing them inside the tent. Then put the plants into the soil and make sure they are adequately covered — usually, cuttings that have developed a root system or plants that are roughly a month old are the best way to go.
After that, water your plants with water that is at a 6.0 pH level and doesn’t have any added nutrients. Don’t overwater them — 8.5 ounces near the stem of your plant is perfect. It is easy to overwater a small plant in a big pot, so be sure to be extra cautious of that. All the soil in the pot should not be wet.
Next, cut a screen to fit the area of your grow room (or tent) and hang it, so it’s about 15 inches above your marijuana plants. Only do this if you have between 20 and 25 more inches of space above that, since that is where the lamp will need to hang when your plants are as tall as the screen. Use cable ties to attach the screen to allow for some movement.
Once the branches of your plants grow through the screen by four inches, begin tying it and retying it as it continues to grow. It should create a blanket of sorts at one single height.
Scrogging: the 5-step edition
- Place a screen at 20 to 25 inches from the pots.
- Cut off the top cola of each plant.
- Prune bottom branches when top hits the screen.
- Force into flowering 2 days after pruning bottom.
- Attach all branches horizontally to the screen.
See? Scrogging is simple!
Perhaps the most important aspect to consider when setting up this method is having some kind of wire or even a tight rope to act as the SCROG screen. A sturdy screen that can hold back the top canopy and has 2-inch by 2-inch squares built in will certainly be adequate.
The “screen” must be set correctly.
You are effectively “training” the marijuana plants to grow in your desired direction without doing anything harsh that could adversely affect growth. The distance between pots and the screen should be 20 to 25 inches.
Tip: make sure to download my free Grow Bible for more information about scrogging
Why does the screen height matter?
When you have limited vertical space or limited light emission the screen keeps the plants lower. It also allows the light to concentrate more evenly on each of the plants.
That’s not all…
The plants are now forced to grow horizontally, which will produce more “useful” plants in the long run.
How to get the most out of scrogging
The scrogging method isn’t just about setting up a screen and watching your marijuana grow. Although very little work is involved in general, you will still need to take great care if you want to SCROG correctly.
People who successfully SCROG also:
- Top their plants
- Attach them to the screen
How to top?
Start by cutting the top colas off each plant when the plant is around 10 inches tall. This encourages the plant to create new branches that you can manipulate in any way you please. The ideal way to manipulate the new branches is to wait until they have reached the screen. At this point, the tops of the branches will be slightly poking through one of the holes in the screen.
You’ll want to continue to take each branch from each plant and move them over to the next hole so that horizontal growth can continue relatively unimpeded. You could also bend and attach all the branches to the screen with some wire horizontally.
When to start SCROG training
Here’s the thing:
When your growing space is small, you could run out of vertical space if you let your plants continue to grow vertically. However, if the marijuana plants are “trained” to grow horizontally, you will ultimately get more yield and a better canopy later on.
You can maximize your grow if you time it right.
Just before the top of the plant hits the screen, cut off all the small branches and side shoots at the bottom. This gives a boost to the top colas because there will be no energy wasted on the growth of useless and small side shoots and fluffy buds.
The process of taking the branches out of one hole in the screen and placing them in a hole farther away from the plant base is often referred to as “tucking.” This should be carried out with the utmost care as any breakages can cause your marijuana plants to reduce growth.
Some marijuana growers like to make their screens adjustable so that they can raise the “ceiling” if the growth becomes too abundant. This is really beneficial if you want to keep your plants in vegetative state for as long as you can.
Another way to ensure that the plants produce higher yields is by maintaining a relatively even canopy all the way across. This will involve cutting off the top portion of a plant to shorten it and also make room for deviations in the branches.
The more branches you have, the more you can continue tucking. Since the growth is diversified and the light is hitting every viable part of the plants, the yield will increase when harvest time comes around.
One thing people always ask me is when they should harvest their plants. This free PDF doc gives a perfect idea of when to cut your plants.
When to stop SCROG training
Because scrogging is an indoor growing technique, the shift between vegetative state and flowering state will be up to the individual grower with some variance based on how you are growing.
For instance, if you’re using a hydroponic system, you might be able to take the plants from vegetative growth into flowering within a matter of only 3 to 4 weeks. If the plants are in soil, it should take around 6 to 8 weeks.
Force starting the flowering stage is something almost based on intuition. You can see when the plants have sort of maxed out their vegetative state. You will obviously want to visualize how much the plants will continue to grow once they enter flowering. When you decide to go for it, put the plants on a 12/12 light regimen.
Then, growth will start to increase as the plants begin to flower extensively. Carefully train all branches and shoots through their individual slots in the screen. I always force my marijuana plants into flower just before they start to grow through the screen.
How much can you yield when you SCROG ?
So how exactly does scrogging work, and how does it actually help?
I can’t say this enough:
The more light, the better. The most obvious benefit of scrogging is the fact that it doesn’t waste any light at all. Energy costs money, and wasted light is a waste of yours. Because of the impenetrable blanket of leaves that you’ve created, all of the light will be absorbed.
But that’s not all:
The fact that the plants are all the same height is a huge benefit. It allows every plant to get as much light as possible because none of the plants are shading the others, and none of the branches or leaves are being shaded.
Want even more benefits?
Try bringing to the lowest possible level (since there isn’t one taller plant that would get burned), therefore maximizing the light intensity. Of course, be sure the temperature doesn’t get higher than 77 degrees Fahrenheit!
You can see the benefit of scrogging during the actual flowering phase as well. Any branches that didn’t make it through the screen should be pruned, meaning your plant won’t develop any buds that aren’t receiving much light.
This matters because:
All of the buds will be top quality, with no fluffy or soft buds that never ripen left to waste your plant’s resources.
Ultimately, scrogging can increase your marijuana plants’ yield by up to 20%. It takes a bit of fine tuning before you’ll be consistently getting these yields, but of course, the effort is certainly worth it in the end!
Some useful tips
Only use clones or feminized seeds
Only use feminized seeds and clones, since, with scrogging, it is crucial that all of your plants are female. If half of your plants were male, they would need to be removed, leaving a huge gap in the screen of green. You can see why that’s not an effective strategy.
Therefore, it is essential to ensure that you only have female plants by either using clones or by purchasing feminized seeds. Remember, you won’t know if your plants are male or female until they are into their flowering phase, so be sure to be proactive about it!
Switch to flowering stage when the screen is filled
As a good rule of thumb, your marijuana plants should remain in their vegetative phase until the mesh or screen is completely filled up. There should be no major gaps. Your plants become the bushiest during the vegetative phase. Even though the flowering phase is the most rewarding, the vegetative phase is also extremely important.
During the vegetative phase, make sure to bend any parts that are poking their way upwards back down. You want them to remain on the same plane as the other parts of the plants. This will allow all the plants to grow upwards in even rows, maximizing the energy from the grow lights.
Scrogging is a simple growing technique that can make a significant impact on your yield. Once you learn how to do it correctly, you can enjoy even more from a single plant. It all comes down to the screen, however, so make sure you choose the right gear. This is definitely one of those times when patience and attention to detail pay off.
Thanks for reading. Check out my most frequently asked questions below and don’t forget to download my free grow bible.
Frequently asked questions
Does scrogging guarantee a better yield? Any type of training can increase yield, but if the plant doesn’t have an ideal environment, it will not thrive. Learn how to create the best environment in this article.
Does it matter how many plants you SCROG? Scrogging is effective on any number of plants. The idea is to train a plant to grow wide. When combined with topping, it can also keep a plant from growing too tall.
How high should I set my screen? Where you set, your screen is up to you, choose based on your needs. You could make it one foot or two – just remember that the higher you go, the more pruning you’ll need to do beneath the screen.
How close can you put the lights? For the best results, you want your lights to be as close to your plants as is safe. If the lights are too close, you could burn your plants. However, that number varies depending on the lights. Read this article for more information on lighting.
What about scrogging in a hydro setup? It is difficult to make changes to your solution once your plants have created a sea of green. You need to plan for this. Therefore, if you are growing hydroponically, use the Ebb and Flow method. Learn more about hydro growing this article.
What happens if you don’t top the plants? The SCROG technique teaches plants to grow horizontally, but it doesn’t keep them from growing vertically. If you don’t top your plants, the top shoot can grow right through it. Learn more on topping in this article.
The founder of I Love Growing Marijuana, Robert Bergman, is a marijuana growing expert that enjoys sharing his knowledge with the world. He combines years of experience, ranging from small-scale grows to massive operations, with a passion for growing. His articles include tutorials on growing... [read more]