So I found this guide somewhere, where it had been posted from somewhere else so I've no idea who originally wrote it but I've had to edit it to remove some inaccuracies and add some bits. Hope you find this useful
The Scrog Method
ScrOG or SCREEN OF GREEN is one of the most productive and easiest ways to grow indoors. Now lets not get this confused with the Sea of green method. SOG involves no training nor does it have one item a scrog always has. A screen. Scrog has been around for many years. Before HID's were introduces many growers used CFLs with this method with good success.What is a scrog? What is the screen of green? Well, it is just that. A screen is the main character of scrog. It is usually made of string or something sturdy enough to hold back the growing canopy. This string should have some holes in it about 2 x 2 inches in size so that the plant matter can easily grow up through the screen and be supported by it. The string is secured between the growing medium and the lamp. The plants grow through the screen about 3-4 inches and then are pulled back under and spread out where YOU want them to grow. It's as easy as that folks. It's a great way to grow. Let me put it this way. I have seen growers get 40 ounces from a 1M x 2M screen with hydroponics and only 2 PLANTS!!
Sounds cool right? So, what are you waiting for?
Getting Started
If you've already got an area where you established plants growing you are halfway there.
The Screen
Remember at least 2 x 2-inch squares. DO NOT use chicken wire – fishing line or string that will fray. Chicken wire is a nightmare to cut out of buds, the fishing wire will cut through stems and you don't want bits of frayed rope or string in your buds. Washing line string or anything similar is ideal really, but I would suggest anything except those 3. You need something strong to support the buds and hold back the canopy growth. The screen needs to be cut to size. The size of the screen is determined by the size of your grow lights. It wants to be the size of your light's footprint at its ideal hanging height. Once you've determined the size of your screen and cut it to size, situate it over your grow area and secure it into place. This can be done using legs or hanging the screen from the ceiling.
How Many Do I Need Under The Screen?
Having fewer plants can be a good thing if plant limits affect you. With fewer plants, you will have to veg a bit longer but you should still get the same yield more or less. I've seen it recommended a lot that 4 plants per square meter are standard however I would do 1 under that and stagger 2 plants so 1 is vegging while the next flowers.
Spacing
This space will need to be large enough to allow you room to manipulate your plants during the training phase. I usually use around 6 inches above the rim of your pots and 20ltr pots. Some people use more. Some people use less.
What Is The Best Strain To Grow In A Scrog?
Almost any plant strain can be grown without much difficulty using a scrog. The secret is in the screen. Some strains require more training than others but that is the only difference. Heavy yield indica's are excellent scrog candidates but the unruly Sativa can really shine with proper training and timing.
Hydro or Soil?
Here are some things you may need to consider before your plants get tangled up in the screen.
Hydro:
Will you be able to maintain the res in your system.
Will a bacteria problem be possible to wash out.
Can you measure your liquids in the system easily enough from underneath the screen?
Soil:
Soil grows and scrogs are a wonderful thing. Organic buds rule. One problem you can run into when Scroging with soil is the flushing of the medium at the end of the grow. Well, with the plants tangled in the screen, you cant just move it to the sink and flush. With organic soil, this is a non-issue as you don't need to flush. (Yay BioTabs) My soil buckets drain into catch pans, then I have to drain the catch pans. If you need to flush, this would be a nightmare!
Managing the Scrog Grow
Vegging: Here is where a lot of people make mistakes. They get in a fired-up hurry and get confused somehow. Flip their shit over to 12/12 way to soon and wonder why their screen never filled up. At that point the screen is nothing more than a support system for the plant. Normally one would veg a plant till the screen is 70-80 percent full before switching over to the flowering cycle. Having knowledge of how much your strain stretches is helpful when determining when to switch to flowering. For example: If you had a very stretchy sativa, you would want to start flowering her with much less of the screen filled. Just the opposite for a nice stunted indica. Timing has a lot to do with scrog.
Pulling It Back Through: So you've got some growth through the screen, about 3-4 inches. Just reach under the screen and pull that branch back under the screen and place it where you want it to be. Now I could really get technical and start with the “be sure there is an internode in each hole of the screen” but it really doesn't matter. Just get the growth under the screen. In the next few weeks, you will see where to guide the new growth to best suit your needs.
Training: Scrog is not natural growth for the cannabis plant. Training begins in the pulling it back through section. Try to situate your main branches towards the barest parts of your screen. They will branch out the most and usually be the largest bud in the bunch. Use some kind of uniformity to your laying out of the branches. Remember there's going to be a lot more branching when flowering kicks in, so allow some room for that as well. Lesser buds that are now exposed to more light are then encouraged to grow upwards toward the screen through some defoliation.
Defoliating: If the leaf is in the way of light for a bud site. Then it needs to be removed. Sometimes you can tuck the leaf instead of removing it, but most of the time you can just remove it. When do I do this? Usually when you do a training session, right afterward. This trims away leaves and allows the new sites to get light. You will be surprised at how fast they will respond. Use good judgment when trimming. Too much is not a good thing here. Defoliation continues into flowering ending during the later stages of flowering. It is not harmful at all to remove large fan leaves from buds during flowering if they are blocking light to other bud sites nearby. It's all about light penetration and bud sites in a scrog.
So, you have turned back the timer to 12/12 and it has been 4 days now. The growth from the stretch is starting to show. You get in there and pull all those new shoots back under your screen and put them where you want them to be. A few more days pass. More growth. Now the decision part comes into play. Just how far over the screen do you want your buds to be? If you stop training them early in the stretch. They will grow a little above the screen (maybe 3-6inches depending on the strain). If you continue training them until they start to top out, they will grow only a little more and most of the bud will form right in the screen. This technique is great for those stretchy Sativa's. However, when doing this method keep an eye out for mold and try to have as much airflow between the buds as possible. I have done it both ways and they are both awesome. It may take you a grow or two to get the timing down to where you want it but once you do. I am sure you will be pleased with the results.
Damage Control: If you move branches around and bend them, eventually somethings gonna give. Don't freak out. It's not the end of the world. Cannabis is an amazing plant that can recover from a lot of damage naturally without help from humans but in this case, you do want to help if you can. First aid for the injured cannabis plant is simple. Just support her wound and leave her alone. She will take care of it on her own. You can splint the wound or support it with some heavy gauge wire around the stem. If the break is not that bad and the branch can somewhat support itself. Leave it alone. In all cases. A knot will form at the break and most times an explosion of growth will happen above the damaged area. At times even new growth sometimes sprouts from the knuckle formed.
Flowering Cycle: Once a few trimmings are done and all is set in place flowering in a scrog is pretty uneventful. Good time to start thinning out your undergrowth. You can clean out the undergrowth around day 35 12/12. and strip everything below the screen.
Undergrowth: I mentioned it above but thought I should mention it again. The undergrowth is not that big of an issue here. It's an area that should be kept clear of dead leaves and you should also ensure that proper ventilation can get through the canopy via the undergrowth. If it can't, then thin out some growth. This is an area that is dim and often humid. It is a good idea to clear out your undergrowth as your scrog takes shape. Trim all remaining sprouts left on the stems and any other undergrowth. This will help the plant direct more energy towards the larger buds instead of wasting energy on the smaller ones.
Ventilation: Here's an issue that can not be overlooked. Once a scrog has been established it is a leafy sight to behold. Air circulation becomes critical as the buds begin to form and things start to get packed in the box. 24hr air movement is suggested 7 days a week. Better safe than sorry. Mold sucks.
Even Canopy: Your canopy does not have to be perfectly even. Just close. The idea behind this is even light distribution. We are looking for a field of buds here not a forest like in SOG. If a dominant bud is allowed to overtake the canopy, it is defeating the purpose of the scrog. Bring her down to size with the rest. You want a somewhat even field of buds to deal with. Not a forest of untamed trees. The even canopy is easy to accomplish if you have been following the steps outlined above.
Tricky Tip: Occasionally you will have a stretcher that decides that she wants more light than the rest of her friends. This often happens when the branches are competing for light. If one gets out of hand there is a simple solution to taming her back into the fold of the others and possibly giving her a burst of growth. Reach under the screen and find her stem. Halfway up her stem start to pull her back through the canopy till she is even with the rest. Now where she is bent. Crush her at the bend with your fingers and supercrop it... Just crush the stem so as it would not be able to support itself if it were to stand alone. As mentioned above. It will heal with vigor and you have solved your canopy problem.
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