How To SCROG

I have been scrogging for a number of years now and thought that I would share the knowledge I’ve gained. I understand that many different methods exist for SCROG, but I am going to share my methods. Please feel free to add your comments and also your own methods to the thread if you like.

SCROG stands for ‘SCReen Of Green’ and was coined in the 90s (I first heard it then, it could be earlier) contrasting another popular technique known as SOG (Sea Of Green). The techniques differ in that SOG uses an nth amount of plants to fill a grow space, whereas SCROG tries to develop a uniform canvas using less plants, even just one.

In this tutorial I will be explaining how to use SCROG techniques to maximize canopy space resulting in increased productivity of your cannabis operation. I say maximize, although this can be debated; whereas a single, untrained plant will give rise to a large central cola, which could easily outmatch (in weight) the many colas from a SCROG’d plant, the many colas from a SCROG will result in more flowering material to have the light required to produce top shelf product. Also, SCROGs doesn’t matter what media you are growing in (within reason). I’ve scrogged in peat, coco, and several hydroponic systems. I also believe you can scrog some very large areas out, where I myself have achieved >1 square meter footprints, I’ve seen others achieve much more.

I start my training after 3-4 nodes of the plant have developed (Figure 1). You can use more or less, but when I get to 3rd or 4th node, I top the plant. I try to top just below the foliage that is getting removed. I do this to prevent the stem from splitting apart later on (Figure 2).




Figure 1: The early topping of a seedling will result in 4 mains





Figure 2: Topping too close early on without leaving some stalk can make the central stalk prone to split. In this case, the main stalk was split down the middle, but repaired with a ziptie.

Following the initial topping, the plant is left alone for another 2-3 weeks (depending on vegetative speed) before I again top each (of the four) mains. I leave at least one full node in between cuts (Figure 3).



Figure 3: After the production of four main stalks, the plant is allowed to grow until several more nodes appear. Nodes (on one main) are numbered + circled in red. The plant is again topped at the (circled) 3rd node.

The idea of this kind of topping is to get a geometric pattern that will allow for a large canvas area. A little bit of branch LST (light stress training) is used to separate the main branches, but otherwise the plant is left alone to develop vertically.

Let’s take a top view look at what is going on. You can see in Figure 4 that the first cut (blue circle) results in the production of four mains (in blue) which are allowed to grow, and then are cut once more (red circle) resulting in a total of eight additional tops. This doesn’t include the extra nodes you left in between either. By doing it this way, you allow your plant to reach each direction pretty evenly.


Figure 4: geometrical representation of topping tactics.

The plant is then allowed to grow vertically until the desired height is reached.

But what is the desired height? That depends on how the dimension of the desired scrog. Let’s say you have a 3’x3’ tent (one square meter), I would probably plan for ~8-10” distance between the pot and the trellis net. There is 1.5’ distance in each direction from the center of the tent, meaning that I would need ~1.5’ (=18”) plant height + the 10” stalk height (ie. 10+18 = 28”); but this is considering ‘right angles’ so add a couple more inches, say a ~30-32” plant height from the soil (not including container) (Figure 5).






Figure 5: A) 3’x3’ tent would ideally have a plant of ~28-30” height following training. B) plant measurements after the trellis is set.



Once the plant has reached the ideal height (28” in this example), we will be adding a trellis net (ie. screen) but first, lets talk about HST (high stress training). Its not really called HST, but given that this sometimes feels like I am breaking someone’s arm (icky) I figure it’s a reasonable term. We want a plant that is going to be 10” tall from pot to trellis, sometimes the mains are easy to just guide to the sides, but most likely, you will need to gently bend the branch with a slight twisting motion at the ~10” mark. I find that this part is easily done if I take all the foliage from one-main-at-a-time and tie it all together (with a string), so that I end up with four bundles of foliage. I then start below the 10” mark and start bending slightly, twisting the entire time. Sometimes I hear/feel the crankling sound; this is normal and the stem will repair itself, but be careful not to crack the main! You want to do this for each main in each direction (N, S, E, W). *If you have a 2x4 tent, you will want to set main to point to each corner instead.

Now we lay the trellis down. I’ve tried some polyvinyl trellis nets with 2” holes (figure 6a), but had to support them by running a length of fiberglass (or bamboo) down the lengths. The reason is that the plant will push the net up, even if its tied down at the corners. This isn’t a huge problem, but lately, on larger scrogs, I’ve built a support out of ½” PVC pipes and used a plastic lattice normally used on decks (Figure 6b). I find this heavier and better suited given that the spacing between each hole is already pre-set.


One nice thing about the lighter (6A) trellis is that it can be ziptied directly to the inner poles of the tent.




Here’s an example of a trellis using the lighter material:


Figure 7: sides of the trellis were supported with a fiberglass driveway marker and then ziptied to the inner poles of the tent.



Here’s a closer look at the bent mains (HST):



Figure 8: Closer look underneath the trellis of a scrog’d plant.

I wouldn’t recommend using the lightweight trellis for a larger area though. Either create a stiffer trellis, or purchase a lattice structure and build a cage as seen in Figure 9.



Figure 9: ½” pvc was used to create a support cage for a heavy lattice used during scrog.



Once I have placed the screen down onto the plant and everything is tied down, I begin positioning each top to a specific opening. I don’t want them too close to each other (but I’ve done it) and would rather use the heavier lattice because it allows some space for each developing bud. But I want to make sure that there is a top or a node at each hole. If the tops are too long, I cut them, or just leave them out the sides.

I should mention that the trellis is usually dropped during the veg-flower transition period. Given that each cultivar/plant will stretch differently, you sometimes have to place the screen a little bit into transition; sometimes I place the lattice after one day of flower (if the plant is known not to stretch much), but sometimes I wait a week+ and then place the trellis. If the plant is expected to stretch a lot, wait a week (after 12/12 is set) and then use the net or you will get stretchy monsters!

I continue to set the individual nodes and branches to each hole. Foliage that is too short to reach the canopy is cut off. Foliage that is too long is repositioned. I get this done in the first couple days after the net is placed and then I let them be. *Do not cut/top any tops during transition or during flower period; you can supercrop branches that are too tall.

Experimental: remember we left the central nodes between the 1st and 2nd toppings? These branches can be used to fill up the central part of the trellis. I have lately been crisscrossing these 4-8 branches at the center, but this is tricky to do without a partner (maybe use some twist ties?).

This is going to be tricky to draw… Figure 10



Figure 10: branches developing from the lowest bracts (off the mains) are crisscrossed at the center of the plant. This is opposite of the way the mains were bent during HST. This is done to get some colas in the center of the trellis.

 

I’ve added a few more pictures to help people understand the concepts I presented.



An example of training between 1st and 2nd topping. This made the HST easier later on. Note that much of the bottom has been defoliated (lollitopped).




Before and (one week) After



Before, immediately After, and a few weeks Later.

 

Adding a couple more under-the-canopy pictures and a picture of the crisscrossing that I explained earlier.

You can see the knuckling on the stalk that occurs due to HST.


Innermost branches off mains are crisscrossed at the center of the plant to fill the center area up.

 

Each node produces a new top on either side.I cut off the top 3rd node, so I have two nodes remaining, which will produce four new mains.

 

Yes there is a danger of that; its part of the reason I recommend leaving some space above the node that was topped. Also, when bending the mains, I press the mains towards each other a little so that splitting doesn't happen. Better to make multiple small bends than all at once.

*edit: here's a closeup of the topped area. Note that I left a stub on.

 

@ the same time.