SCROG philosophy is few plants, big production. SCROG ( Screen of Green ) is a technique of growing marijuana indoors for which a mesh ( screen ) or net is used.
Instead of growing tall, in SCROG the plants grow in width by colonizing the mesh until they form a homogeneous green mass , thus optimizing the use of light since each tip will be at the same distance from the focus.
How is a SCROG crop made?
SCROG is a very effective and easy maintenance technique , although it takes a lot of work in two moments, when tying the branches to the net and when harvesting.
How many plants are used in a SCROG?
For each square meter of cultivation area we can put from 1 to 8 plants, although the ideal number of plants to make a SCROG is 5 or 6 per m2. The less you use, the longer it will take you to cover the net or you will waste light in lighting areas without buds. Since you assemble the system, take full advantage of it by getting the maximum possible harvest with the same resources.
For the recommended proportion of plants, the final pots will be about 12 liters (in soil). If you put fewer plants, in order for them to develop to the maximum you should use larger pots (25 L if you only put one).
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What meshes should be used in SCROG cultivation?
There are many options that you can use. The most common is plastic mesh that is used on construction sites, and you can get it at construction material stores or some large hardware stores, but it is only used indoors and without a fan, since the edges are sharp and with a wind could damage the branches. The best, without a doubt, is the framework of bamboo canes (finite, maximum 8mm in diameter), but it takes time to manufacture.
Of course, if instead of bamboo you have rods from other woods, it works equally well. You can even make it with a thread or cord. What you should not use are metal nets (such as corrals or some bottles of cava) because they heat up and can damage the plant. Whatever the material, the net or mesh must have holes of 5 to 10 cm.
How is the mesh placed for cultivation with SCROG?
For a good SCROG, the mesh must be placed above the plants, about 20 or 40 cm above the pots. It is not recommended to place it below because it will be difficult to water and clean the pots, and especially because the plant will not have enough space to remove branches.
When the plant reaches the mesh we must place the branches parallel to the network below, and we will lower the twigs that appear through the holes, guiding them so that they occupy all the possible surface. It can be a bit tedious because you will have to watch day after day as they grow to shape them (if they are sativas, this can be up to the second week of flowering, inclusive).
If a branch grows too large without you guiding it, then you might damage it by suddenly trying to bend it. As soon as a point protrudes more than 8 cm above the net, you must re-tangle it. You can carefully tie it with thread, without tightening too much.
When your marias have been in bloom for a week, let the ends grow upwards. Each hole should have one or maximum two ends.
The two most typical ways of placing plants are at the ends ( eccentric distribution ), with the main branches parallel and the secondary branches perpendicular, or at the center ( concentric ), with the main branches towards the ends and the secondary branches spirally arranged.
As for the mesh, it is not superfluous to place the ends higher than the center (in the form of a U), to achieve the greatest possible homogeneity in light intensity, but this is not applied with fluorescent lamps.
What type of pruning must be done at SCROG?
It is essential for SCROG to tap during growth. Since we want our seedlings to branch as much as possible, the first thing we will cut will be the central bud when it has reached 15 cm. (minimum 3 knots). In this way, the hormones and energy of the plant are distributed through the lateral branches, allowing them to develop more and grow in width, which is what we need to cover the network as soon as possible.
There is a special system to cut the apical bud and get twice as many shoots as with a normal cut. It is called FIM pruning ( fuck I missed ) and it consists of cutting almost the entire shoot, but leaving 20%. In this way, we can get up to 4 times more branches.
When we put them to flower we will do another pruning, this time of the branches or leaves that have been below the mesh and do not receive light.
When does marijuana start to bloom in SCROG?
We will control the flowering cycle with light. While it is growing, we will give it a light cycle of 18/6. Then, when the mesh is largely covered, we change the photoperiod to 12/12, and thus the marijuana will enter its flowering period. If it is a culture of indica, which suspend growth earlier, we will have to have the mesh covered by 85% practically, but if they are sativas, when the mesh is 50% it is time to move them to flowering. This is because sativas continue to grow quite a bit even when they are flowering, and they will have more time to finish covering the net.
The growth period will then be approximately 5 to 7 weeks with indica or few plants, and 3 to 5 weeks if you use sativas in the recommended ratio. Remember that the intensity of light is decisive in the growth of plants. If you don’t know the genetics of your seeds, treat them like sativas. Otherwise you run the risk that they grow excessively and get too close to the foci.
What advantages does SCROG offer?
Much of the effectiveness of this marijuana growing technique comes from using very few plants. One of the great advantages of this is that it is not necessary to buy many seeds and we can invest a little more in the quality of the genetics that we cultivate. The other great advantage is that since there are few plants, there are few pots that we have to water, and maintenance is almost labor-free.
Given the homogeneous distribution of the tips, the SCROG method is suitable for lighting with LEDs , since the light is not required to penetrate too much. Also, in the growth stage, you can use fluorescent bulbs or low power bulbs. Both options will help us save on the electricity bill.
The Screen of Green is also used in outdoor crops so that the plants do not grow as high and stand out (especially if you live in a city), while also making better use of sunlight.