Tips & Tricks for the SCROG Method
The SCROG method is one of the most efficient and productive ways of growing cannabis. It can be done in both large and very small grow boxes with limited space, while preventing plants from growing too tall.
In the SCROG cultivation method, in contrast to the SOG (Sea of Green) only a few plants are used in combination with a net or a grid. The aim is to fill the entire cultivation area with large and heavy buds, i.e. to form a carpet of flowers. SCROG comes from Screen of Green.
With this method, a wide-meshed net or grid is placed between the light and the cannabis plants. Most growers use clones because they grow absolutely homogeneously and their growth structure and expected height are already known in advance. Cuttings are the easiest way to achieve an even and comprehensive flower carpet.
Of course, plants grown from seed can also be used for scrog cultivation. But these should have a very similar growth habit and a fairly similar flowering time. So Sativa and Indica in a SCROG grow will be difficult and not effective. It is better to use either similar Indicas (Indica dominant strains) or very similar Sativas (Sativa dominant strains) for a SCROG grow.
In a SCROG grow, each plant should have at least 30 x 30 cm at its disposal, which means that no more than 9 cannabis plants should be placed on 1 m². With some sativas or hybrids it is also possible and reasonable to fill a m² with only 1-2 plants. With SCROG, 1-5 plants per m² is a suitable number.
The cannabis plants are not sent into flower until they have covered and occupied at least 70% of the net/grid. As the marijuana plants grow through the net, they are trained and fixed to the net and shaped. All main stems and side branches are trained into the appropriate shape under and on the net.
SCROG principle
With the SCROG method, instead of a single headbud, many large flowers or a dense carpet of flowers should develop under the plant light. When the cannabis plants grow through the net (grid, screen), they are simply fixed and tied along the net/grid as already described. This is repeated until the entire screen is covered in green.
The right light for SCROG cultivation
To achieve good results and get really potent and strong buds and an abundant harvest, use NDL sodium vapour lamps or High Power LEDs with the appropriate light intensity for lighting during the flowering period. With the right and professional setup, yields can be increased to the absolute maximum and huge fat buds and flower clusters can be produced.
To create a green carpet of plants that will later become a carpet of flowers, a wide-meshed net or grid is used, which is fixed horizontally under the lamp.
Various SCROG net and trellinets are available for this purpose:
Trellis nets and grids
For the SCROG grow, wide-meshed nets or also grids made of plastic, nylon or stainless metal are used, which are already available ready-made in various designs and sizes, or you construct your own net from hemp strings, clothesline or a grid made of thin bamboo sticks, which is also a good thing because it is very robust.
After each pass, the SCROG net/grid should either be discarded or thoroughly cleaned and disinfected.
The net is fixed above the plant pots at a fixed height:
- for Indicas, the net is installed about 20 cm above the pot
- For hybrids, average 30 cm distance from the plant pot, depending on the variety.
- for sativas approx. 45 cm distance from the plant pot
- with some Haze and Thai varieties even approx. 60 cm distance to the pot
SCROG-Grow and the implementation
Many plants already start to branch under the net, but if not it is a germ problem. The branches are trimmed or trained anyway.
The light should in any case be provided with Height-adjustable hangers because it must be constantly adjusted to maintain an ideal distance between plants and the light and thus get the most out of it.
With SCROG-Grow, the plants are left in the vegetative phase longer than with SOG. On average, a SCROG grow lasts 1-3 weeks longer than a SOG.
With the SCROG method, the plants are trimmed to a horizontal and extensive growth and trained until the 2nd week of the flowering phase. From then on, the flowers are also allowed to grow vertically through the planting net. The main stems and thick branches are still fixed to the net in the direction of the light and placed so that they always get the best lighting.
When the vertical flower growth starts (from the 2nd week of flowering), simply press the large sun sails under the net so that the light reaches the flowers and branches and they are not covered.
In case of excessive leaf growth, large leaves that cover a lot can first be shortened by half with disinfected scissors so that more light reaches the flowers. Half leaves can still provide energy for the plant. If you cut the leaf off completely, this can inhibit growth in some varieties. In about a week's time you can cut off the large leaves that have been cut in half. You can also leave the half leaves on. However, I remove them so that more air can get to the flowers and circulate. This prevents the occurrence of fungal diseases and ensures that more light reaches the side branches.
It is advisable not to cut off too many leaves at once per plant, so that the shock to them is not too great. It is better to do this in several stages with 3-4 days in between, if it is necessary and sensible to remove several leaves from a plant. Only remove leaves if it makes sense for development and better exposure, otherwise it is better not to. Some varieties have so few leaves by nature that it is unnecessary and not helpful to remove them. On the other hand, there are some leaf-ultra-volume monsters that can very well tolerate pruning within a SCROG.
As described, the flowers start to grow vertically from the second week of flowering and increasingly form a dense carpet of flowers above the net. Now it is time to cut off all the leaves (often already yellowish due to lack of light), weak twigs and small flowers below the net, which never get right anyway. The carpet of flowers and leaves above the net has already become so dense that the light is blocked and can no longer get underneath. Cutting off these lower branches allows the full energy of the plant to reach the thick buds above the net. Any small branches that have not made it to the net by then can be removed. Nothing will come of it anyway and it takes energy away from the cannabis plant.
Again, proceed carefully and never remove too many branches or leaves at once to avoid causing developmental delays or restrictions.
Various forms
The SCROG method can be used for both soil and hydroponic growing. There are different forms of SCROG but all are based on the same principle:
- V-SCROG or U-SCROG: net or grid in U- or V-shape
- Flat SCROG: the plants are kept flat overall and brought into shape
- Cylinder scrog or vertical scrog
It can take a little time, perhaps a few grows, to perfect the method for yourself and gain some experience.
If the set-up is right and everything has been done correctly in SCROG cultivation, 95% of the available light can effectively be directed directly onto the flowers. The result is a dense carpet of flowers that is ideally illuminated 12 hours a day and delivers increased yields accordingly.
What should be considered when growing SCROG?
The cannabis plants should not stay too long in the growing phase, so that they do not focus their energy on developing too many branches and leaves instead of flowers. On average, cannabis plants stay in the growing phase for 7 weeks at a SCROG. Of course, this always depends on the strain.
In addition, care should be taken not to break twigs and branches, because twigs will reappear in these places and energy will then be directed to the formation of new twigs. It is better to bend the branches carefully to fit the net and when scrogging.
Of course, the SCROG method can also be used for perpetual growing. In this case, growers often use 2 or more independent screens (nets, grids), so that a constant change and exchange of plants is possible. When a screen is finished with plants and harvested, a new one is placed in its place with young plants.
Which cannabis strain for the SCROG?
Basically, you can use almost all strains for indoor SCROG cultivation. Especially large sativas can be brought under control in their height and size and can often only be successfully grown indoors.
It is logical that for a SCROG with Sativas or Sativa dominant strains on the same cultivation area, you need and should use fewer plants than if you grow Indicas.
Some cannabis strains are better suited for SCROG cultivation than others. In our seed shop you will find information about this for many strains. With a little experience, practice and experimentation, you can grow your own adapted, highly productive indoor garden.
Pot size and growing season
Usually one uses larger pots for SCROG and of course much larger than one would for a SOG:
- With 3-5 plants per m² approx. 12 L pots and a vegetation period of 3-5 weeks.
- With 1-2 plants per m² 20-30 L pots and 7 weeks vegetation time
Fertilise & Care
In terms of care and fertilising, SCROG-Grow simply implements all the rules and what you would otherwise do in exactly the same way.
You should always ensure good ventilation in the grow room: use sufficiently strong fans, fans and swivel fans (at least 2 per m²) so that the plants and later the flower carpet are well ventilated.