Pruning
When the plant is left to grow as it chooses, it usually has more branches than it has the energy to support. This means that a lot of energy is wasted on smaller branches, especially the lower ones. The energy need is so spread out that in extreme cases flowering takes a very long time as the plant tries to supply energy evenly to every location. By removing some of the less important and weaker branches, you can ensure that the larger branches produce a greater amount of high quality bud. The bud on the lower branches that receive less light usually end up as single “pop corn” buds that never truly mature, so it is best to remove them at an early stage.
You become the investment planner for you plants. Observe the growth and remove any branch that has long internodes (the space between the nodes) and any branch that stays significantly lower than the main shoots. These branches will get very little light and they will also have a hard time finding their way up to the well lit area. Most of the time I end up removing almost all the growth underneath the Scrog net, I only leave the fan leafs intact until the plant drops them by itself after the energy has been recovered.
When it comes to removing leaf material opinions vary, some remove leafs and others, like myself, chose not to. I have tried both methods and can honestly say that there is no positive effect really from removing leafs. Keep in mind that fan leafs are the primary location for photosynthesis and that the plant also stores surplus energy in them. By removing the leafs you do double harm, you handicap the plants ability to produce vital energy and you also remove the energy that has already been stored for future use. Furthermore, although it cannot be observed with the naked eye, light actually passes through the leafs and that is why some of the lower growth stay green throughout the entire grow. It is better to tuck or tie the leafs under the canopy so that light reaches more bud sites, or alternatively cut the leafs in half.
Another thing to keep in mind is that there is a hormonal response in plants to being wounded. This includes a growth inhibitor called jasmonic acid. It tells the plant to favor defense over growth. The more you remove at any given time, the greater the response. It is therefore wise to trim the plants gradually althrough flowering, instead of removing all the growth at once. This hormone also plays a part in regulating the formation of trichomes, and that is probably why a little bit of stress is thought to increase potency. There is however a difference between stress and torture, a healthy plant will always produce more bud than a plant that has been severely handicapped.
Since most of the photosynthetic activity takes place in the fan leafs, the buds themselves do not need light, in other words, bud sites are activated by light when it hits the node but the energy is produced and transported to the buds from the leafs. This is where a Scrog net comes in handy, you can tie down the leafs without removing them and thereby allow more light to reach the buds while no energy is lost.
Sometimes you do not have a choice and must remove some of the growth in order to ensure that you get a good harvest. It all depends, some plants respond well to rigorous pruning but in general I would advice that you keep it to a minimum since there are optional methods to removing the leafs altogether. The rules of pruning are a bit different when it comes to SOG grows as you might have to remove some of the fan leafs because the plants are packed so close together.
I think that the best advice is to watch your plants closely and adapt your technique and grow style according to the needs of the plant.
Nothing is set in stone when it comes to growing.
All grow rooms are different and so is each strain of cannabis. In fact every plant is different from the next so you will have to try out what works best for you and your plants. I hope that this guide at least gave you a general idea of what the methods are and how they can be applied for a greater harvest.
HAPPY GROWING