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The Scrog Guide (Screen Of Green)

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  • Mar 09 2010 07:54 PM
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Posted 09 March 2010 - 07:54 PM

An Overview of Cannabis Training

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Now then. After the reactions that I received on my first dive into guides for training, I thought a more complete guide was necessary as it's something I've done quite a bit more reading into since then and I've also gained experience and insight into various methods. In addition, it seems the same questions are still being asked by newer growers. There are a lot of good sources of information out there on the subject. However, I felt a compilation giving a brief explanation of them, with some examples, would allow everyone to develop a common language here. In addition, it'll help those newer to the hobby, and the forums, so they can understand just what the hell people are saying.

This guide will be divided into five parts:
I) Understanding Training
II) High Stress Training Techniques
III) Low Stress Training Techniques
IV) Sea of Green (SoG)
V) References/Links

No better place to start than the beginning...

Part I: Understanding Training

First, I should go over the acronyms just to get them straight so that we all know we're talking about the same things here:
-ScrOG - Screen Of Green
-SoG - Sea Of Green
-FIM - Fuck I Missed
-LST - Low Stress Training
-HST - High Stress Training

With that out of the way, let's go into a small explanation as to why these methods are used and what they can help you achieve with your plants. We'll start by dispelling a few of the most prevalent myths about training:
1) Training can take place during flower.
2) Training is not just to control the height of the plant.
3) Training can be done for any strain. Though some react better than others.

With those three things out of the way, let's get into some meat and potatoes.

Training can be divided into two main categories:
High Stress Training - HST
Low Stress Training - LST (also a common name for a method of training so be careful with this)

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The two types of training are like they sound: either more or less stressful for the plant that you are training. For the purpose of this guide and according to most of the sources out there, the differentiation is simple:
LST = not physically damaging the plant
HST = physically damaging the plant

Notice that I did not say harming the plant because, well, it's training; none of us are out to hurt our plants.

Both of these types of training produce similar results, but they are done in different ways. Everyone who trains has their preferred method. To help you pick the method that you'd like to choose for your grow, I'll explore the pros and cons of each. We'll go into detail about the different types of training in the next parts of this guide.

High Stress Training
Requires no additional parts (except to cause damage)
Great for larger grows
Creating possible sites for infection
Can backfire if the plant reacts poorly
Mostly irreversible
Mistakes are more costly
Possibly slower recovery time

Low Stress Training
Does not stress plants as much
Reversible (for the most part)
Great for micro grows
Fun to do as it's more involved
Requires additional parts
Takes more time
Possibly less fun to do as it's more involved (just depends on you)
Requires more plant manhandling

Training, when executed properly, has great results that can be seen in both quality and yield for your plants. It can be the difference between 2 big colas and some popcorn to 8-10 large colas:

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Training, whether it be HST or LST, is done for the same reason: to reduce the level of auxins in the tip of the plant. Cannabis is a plant that grows with a characteristic called "apical dominance." This means that, like other plants, it will do everything it can to push a single tip towards the source of light. We call the tip of a plant that grows like this the apical tip or the terminal tip. The tips of the cannabis plants are also where the biggest colas are produced due to their proximity to the source of light.

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The tip of the plant is also where a particular type of auxin (plant horomone) is most prevalent. It's called indole-3-acetic-acid (IAA). Unfortunately, due to the chemical properties of IAA, you won't see it in the rooting horomones you can buy. More than likely, you'll find indole-3-butyric-acid (IBA) and/or a-Naphthalene acetic acid (NAA); other auxins.

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Now, the auxins promote growth when they are in certain levels but they can also inhibit, or stunt, the growth of certain aspects of the plants if they are at higher levels. This is the case for cannabis plants. The plant is perfectly happy pushing one bud up as far as it can to the source of light. The other buds, lower down the branch, will remain auxiliary buds and branching is not as likely to occur in these places. This is especially true in smaller, indoor environments. This is because the auxin production within the apical tip is very high, preventing the lower buds from growing out.

A very obvious example of this is in nature with the pine trees:

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So, training, whether HST or LST, is done to accomplish one of two things:
1) Removing/inhibiting the main source of auxins
2) Making the plant think the apical tip is no longer the best source of light

By removing the main source of auxins, the lower (auxiliary) buds are no longer inhbited. The plant will now concentrate on the auxiliary buds and cause branching to occur in order to get itself a new apical tip. In ideal environments, the plant will grow somewhat symmetrically so that means you can very often more than double the number of growing tips.

By making the plant think it's apical tip is no longer the best source of light, it will send the message (via auxins and other chemicals) to the auxiliary buds lower down the stem that they need to grow up to get to the light. The tip is not removed, but new bud sites are formed further down the stem. Depending on the length of the stem and strain of the plant, you can sometimes get many, many bud-sites to grow this way.

In either case, you end up with more bud-sites closer to your light source than before and, most of the time, you'll end up with a more even, bushier canopy to ensure your lights are being utilized to their fullest.

Now that you've got an understanding of training, we can start to look at some examples

Part II - High Stress Training

Super-cropping, topping, chopping, decapitating, crushing the herd, bending the stem, FIM, call it what you will: it's high stress training (HST). Any time you are physically damaging the plant to train it, you are causing it to undergo a series of chemical and horomonal changes that will result in what everyone is looking for: more budsites on your plant.

There are 2 main types of high stress training:
1) Topping (via FIM or other method)
2) Stem mutilation

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We'll start with topping. Topping involves removing the apical tip from the plant. This causes the plant undergoe a series of changes, resulting in the auxilary buds sprouting new apical tips. As discussed in part I, this is because there is no auxin generator above the tips inhibiting the growth of the sites. This will usually result in at least two bud-sites where there was one.

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Another type of topping is called the FIM method. FIM stands for "Fuck I Missed." This is because, instead of completely removing the apical tip, you are only removing half of it, looking like you "missed" the top. This can results in 3, 4 or even more tops from the location. A common FIM technique, is to bend a box-razor blade so there is a curve in it. This way, you can scoop out the area necessary to make the FIM cut.

DierWolf, from the grasscity.com forums, produced an excellent image that illustrates the difference between regular topping, and the FIM technique:

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So, you might be asking yourself: "if the FIM technique produces more bud sites than regular topping, why would anyone top their plants?"

Now would be a good time to look at the pros and cons of FIM vs Topping.

Potential to produce many bud-sites
More careful methods
Can keep canopy level the same
Great for small grows
Large risk of failure - if you cut wrong, you won't get the results you're looking for
Larger risk of infection - more exposed foliage
More time consuming
More difficult

Does not require tools
Great for large grows
Less budsite potential than the FIM technique
Longer recovery time

FIM is generally known to cause more bud-sites than regular topping but it is definitely more time-intensive. Topping can be as simple as using your fingernails to pop the top off of your plants as you walk along your grow. To properly FIM, precision and a tool must be used for maximum results.

Speaking of fingernails, let's look at the other type of high stress training: stem mutilation. Now, there are interesting theories, methods and discussions invovling both the science and application of this type of training. This type of training is known by many different names:
-Crushing the herd
-Leaning the stem over

All of them have the same general idea: mutilate the stem evenly around an area so that the stem bends over at a 90 degree angle. In this case, we aren't removing a piece of the plant, but rather damaging an area of the plant so that the angle of the branch changes.

The most common methodology for crushing the stem is to pinch the stem enough that it breaks and separates a bit. Then, turn your pinch by 90 degrees and pinch again. This will cause the tip of the plant to fall over at an angle.

Supercropping can be done during vegetative growth to achieve effects similar to LST. That is: the apical tip will be bent downwards once the branch has been pinched. This causes the plant to think that it needs to send new tips to grow towards the light source.

Supercropping can also be done during flower to keep those stretchy plants from burning themselves. There are plenty of examples of supercropping well into flower w/out having too adverse of an effect on the plant:

Obviously, some strains will respond better than others. In addition, if you supercrop well into flower and you have some heavy budsites, you may find the stem has troubles supporting itself. Be smart about it and don't crush the stems too hard if you don't think the plant will grow out of it.

Let's check the pros and cons of this type of training:
Not as stressful as removing plant parts
Less worry of failure
Not as prone to infection
Quick and easy
Somewhat inprecise
Can have a learning curve
Changes for different strains

In the last type of training, I started to talk about how supercropping can be used to trick the plant by damaging the stem and causing the tip to fall to, or below, a horizontal level. This leads us into the basics for the next type of training.

Part III - Low Stress Training

It is easy to get confused about low stress training when you are first exploring cannabis training. This is because the acronym for low stress training (LST) also happens to be the name coined for a particular type of low stress training. No one is quite sure of the source, but many attribute it back to Delta or myMUSICveins (thanks greenisgold) for popularizing the name and the technique.

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There are two main types of low stress training:
1) The tie-down method
2) Screen of Green (ScrOG)

Low stress training does not require any mutilation or damage to the plant which, for some, is the sole reason to use it above high stress training methods. Low stress training is done by tricking the plant into thinking the apical tips are no longer able to be the apical tips. In nature, if a branch gets blocked by another branch, or a large leaf from another tree, the plant will do it's best to navigate the growing tip so that it can continue growing upwards.

If, however, the plant cannot easily find a way to make that growing tip go back towards the light, the level of auxins will shift, and the lower sites will be called upon to try and stretch up to become the next apical tip.

This process can be repeated over, and over again in our controlled, indoor environments: apical tip grows up, apical tip trained down, other tips grow up, other tips tied down, more tips up, and so on.

Now, let's look at the two approaches to low stress training.

First we'll explore the tie-down method that is also just known as LST. There are a couple different approaches to LST.
a) Constantly training a single apical tip
B) Training every apical tip

The first approach involves constantly training, and untraining, the main apical tip so as to utilize as much of the growing pot as possible. TillthedayiDIE420 from rollitup has a great image detailing this method:

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In the image, the 1st large number represents the week. The second large number represents the size of the pot in inches. Although it does not need to be followed exactly, the idea is there.

The second approach to LST is simple: train every apical tip down until you are happy with the bush you have.

There are many different ways to attach the training to the pot and the plant. In addition, there are many materials that you can use to apply the training.

I prefer using clipped pieces of shielded copper wiring. This reduces the amount of time you have to fuss with knots and the pieces are easily reusable.

For attaching, you can attach the tip to the base of the stem to begin with. From there, you can either put holes in your containers, or tie some rubberbands around the outside and pull the training medium down to them. They just snap in place. Very handy and easy, though the rubberbands have to be replaced:

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Now that we've gone over LST, we can look at the Screen Of Green method.

The ScrOG method is almost identical to the LST method. Instead of using string or wire, a screen is fastened to the pot, buried along the edges of the pot and stretched up across the plant, or built separately from the plant. Once the plant has reached suitable height, training can begin. Once the screen is above the plant and the apical tip is long enough, it is bent down and pushed beneath the screen. This will cause the tip to grow horizontally. In addition, it will promote new tips further down the stem. These tips can then be trained downwards for horizontal growth, or trained to grow upwards in the hole of your choosing after some horizontal growth.

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Eventually, the main tip will find it's way to a hole in the screen and start to grow up again. Depending on the size of your screen, you can push it back down and under to promote more growth further down the stem, or allow it to continue upwards with the new tips that you have created.

ScrOGs can be done for single plants, 2-3 plants or multiple plants in a SoG-style setup.

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Once you have a nice screen of tips, or a jungle of trainings from string/wiring, you can send the plant into flower and watch the magic happen.

Now that we've looked at the different types of LST, let's look at the pros and cons of each.

LST (Tie-down method)
Requires very little materials
Can be moved from pot to pot relatively easily
Time consuming (especially if using string)
Materials may be harder to reuse
Harder for larger applications

Screen Of Green (ScrOG)
Easy to train once setup
Screens can be easily reused
Can be done for large applications w/out requiring much time
Cool as hell to look at
Easy to harvest
Requires setup
Hard to transport or move from pot to pot
Requires a bit more learning
Requires planning ahead of time for best results

Since both methods are so similar, it really ends up coming down to a matter of style and preference more than anything. Both produce excellent results and can greatly increase your harvest. This is especially true for micro-growers where every bud-site counts.

Speaking of every bud-site counting, we're going to explore the last bit of "training" for this guide. I put quotations because, well, it's not really a type of "training" at all. Follow along and you'll see what I'm talking about.

Part IV - Sea of Green (SoG)

The Sea of Green (SoG) is not really a training method, persay. However, because the acronym often gets lumped within micro-growing styles, I felt it was worth exploring in this guide.

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The Sea of Green method does not involve training the plants or changing levels of auxins like what we've talked about before. Instead, SoG allows a grower to maximize a variety of cannabis while at the same time trying to dial in a strain/method that allows for the most grams per watt.

The SoG method involves growing many plants in smaller pots. Usually this is done with clones. There are quite a few different growers who utilize the SoG method in these forums. SoG can be done on smaller scales in containers such as cut 20oz soda bottles, or it can be done by utilizing taller, 1/2-3 gallon containers, with less width. By allowing for more plants under the light, one can grow many different strains without worrying about the canopies interfering with each other as much.

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The idea behind smaller SoG grows is to get bud from the soil to the tip of the plant. This is a strain-dependent characteristic, but is often a desired one from SoG growers.

Let's take a look at the pros and cons of this method.

Easier to grow more strains
Clone friendly
Can potentially mean increased yield
Higher plant count
Not good for all strains
More time-consuming

SoG is great for some who want variety and a bunch of colas sitting in their flowering chamber. However, the small size and number of plants is just too troublesome for some. Now that we've looked at the main types of training, you can make your own decision and go out there and start maximizing your yield.

But don't just take my word for it...

Well, that's it everyone!

I hope this has allowed you to make a decision as to the type of training you want to do. From here, there are many resources available for detailed information and pictorial examples for the type of training you decide upon.

Mostly, I just hope this guide lets you put more buds under the lights:

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I hope you have found this guide helpful :)
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Replies (22)

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Posted 09 March 2010 - 09:37 PM

+rep good stuff :hello:

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Posted 09 March 2010 - 10:13 PM

This needs to be stickied :D

Great guide, cleared up a lot of questions I think.

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Posted 09 March 2010 - 10:20 PM

I'm doing my 1st LST/LED grow now, I'm using the coil technique, when I'm tyeing the girls down :) I've not been to confident, I've read several LST threads, its good to see another thread to re-assure me that I'm doing it correct, K.I.S.S.

1week veg & 1week veg + 1week flower

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Posted 10 March 2010 - 03:50 AM

appreciate it guys hope this helps whoever it can :)

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Posted 10 March 2010 - 04:09 AM

Mod should sticky this! very well put together guide! :hello:

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Posted 10 March 2010 - 05:04 AM

hell yeah, good stuff!

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Posted 22 April 2010 - 01:00 AM

AUTOFLOWER, or anyone else ever put a screen up to do scrog when plants are 2 feet tall n almost ready to flower? I know it won't be as good as starting from beginning but just wondering if there are any downsides to doing this? thanks for any info!

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Posted 01 August 2010 - 03:59 AM

Great guide Autoflower. Just had a quick question for you.
Do you think a plant could be, hypothetically speaking, fimmed and then LST'd and then SCROG'd? Or would all the cutting and bending be too stressful on the plant?


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Posted 01 August 2010 - 01:36 PM

auto flower

please give credit to the original poster of this .......

and it is already stickied in the Plant Training Forums


Edited by Wharfrat74, 01 August 2010 - 01:44 PM.

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Posted 02 August 2010 - 05:11 PM

this fer sure needs to be stickied great info in here

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Posted 03 August 2010 - 09:17 PM

Definitely sticky this. Might want to change the title to "An overview of training" or something like it.

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Posted 03 August 2010 - 10:23 PM

well done!! loved reading through this explained alot that i didnt know about, cheers

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Posted 03 August 2010 - 10:54 PM


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Posted 20 October 2010 - 01:51 AM

Nice guide. Any thoughts on off-shoots of these methods like a vertical ScrOG? Couldn't it be possible to train the plants along a vertical axis and through the screen? My DIY box has more vertical space than horizontal so it seems a vertical ScrOG would be appropriate.

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Posted 21 October 2010 - 06:57 PM

Not sure why this is called the scrog guide, it should be called "LST Defined". Great general overview of basic LST terms but very little scrogging info.

I agree. A great resource but not ScrOG specific.

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Posted 21 October 2010 - 08:12 PM

Great info. +rep

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Posted 22 October 2010 - 11:31 AM

auto flower

please give credit to the original poster of this .......

and it is already stickied in the Plant Training Forums


Give credit to one person who did a guide on this 6 years ago? I think thats a bit... pointless seeing as that person no longer posts on this forum. There can be more than one guide to a method and as good of a guide that he wrote an update is refreshing. This is well done and has very very good pictures. I got a lot out of reading the first guide, I have got even more out of reading both. He didn't copy information from him he just wrote a detailed guide on multiple methods, not just one and he gave credit where credit was due on some of his pictures. He has all methods in one post with detailed pictures and explanations. Thanks for the post this SHOULD be stickied in my opinion.

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Posted 08 October 2011 - 05:56 PM

Simple question no one seems to be able to or want to answer. And I have to believe there are people out there that have tried it and know the answer.
When using the exact same hydroponics system, lighting, grow space, fertilizer, strain of cannabis, two months veg/two months flower.........ie; everything exactly the same except the growing style.
Which style produces more grams of bud, SOG or SCROG.
I have heard SOG produces massive buds but am not concerned with that. I want to know which grow style produces the most grams of bud regardless of the size of the buds. I would gladly go with more total bud before massive bud size. If many smaller buds in a SCROG come to more total grams than a few massive buds in a SOG then scrog is what I want. Most production not bud size is my goal here. Can anyone help me out on this?

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Posted 08 October 2011 - 06:32 PM

I would say the extra time it takes to veg a ScrOG would give you more bud, but take longer. Really, I think they even out.

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