How do I prune cannabis plants correctly?

There are almost as many theories on how best to prune cannabis plants as there are different strains. Proper pruning can and should channel the plant's energy into the largest resinous buds and influence the growth structure in a certain positive direction. The most important thing here is to follow a precise plan and not just aimlessly chop away at the plant. It is not necessary to prune cannabis plants in order for them to grow well, but for some strains, cultivation methods, to limit the height and to increase the yield, it can make sense.

Wilted, more damaged and diseased leaves should be removed with a clean cut and are only breeding grounds for diseases and vermin.

There is Cannabis strains that do not respond well to pruning as a training method or can't tolerate it at all, it's impossible to make a general statement. The best thing to do is to refer to the information on the varieties, ask experienced growers who already know different varieties or simply try it out yourself. Be warned not to remove the large awnings. These are the nutrient store for the plant and contribute an important part to its nutrition and development. If you simply cut them off uncontrollably and especially too early, the plant will be significantly weakened and will react annoyingly in various ways. With sativas and automatics, i.e. auto-flowering cannabis varieties, you should definitely keep your hands off. However, it can make sense with Indicas and Kush varieties with huge leaves towards the end of the flowering period. Leave or remove awnings and leaves?

Before trying out pruning and gaining your own experience, you should first decide on a cultivation method. This will determine when, how and if a cannabis plant is pruned. Not all pruning techniques are suitable for all methods of cultivation. This means that with sea-of-green cultivation, for example, you have to follow a completely different approach than, for example, with „Lollipopping“, Super Cropping or Growing Monster Plants outdoors. Proper pruning of cannabis plants is an art in itself and requires some time, practice and careful planning.

Pruning can be roughly reduced to two ways:

a) pruning to restrict side branches and growth and
b) Pruning to stimulate and promote side branch growth.

Cannabis plants with strong height growth: pruning to limit growth

Indoors, plants that are too tall waste energy getting all the nutrients and water to the side shoots and tips, which are a greater distance from the roots. The biggest buds always grow at the ends of the branches. It should therefore be as easy as possible for the plant to deliver nutrients to these buds. Much less light reaches the lower buds, they only become small and airier. This means that the small leaves and flowers at the bottom of the plant only waste space and take energy away from the big buds higher up.

You can plan ahead and influence various factors to prevent cannabis plants from reaching too exorbitant a size:

• An important point here is Sufficient light. If, for example, you were to put an indoor sativa in an air-conditioned room and hang a lot of fluorescent tubes high up on the ceiling, in the best case you would get long, giraffe-like, curly, very very long and bright yellow plants that try to reach the light right up there on the ceiling. This means that sufficiently strong lighting, even in the growth phase, can help prevent overly tall and elongated growth.

• Mit Hilfe von Topping, also dem Beschneiden des Hauptriebs durch Abknipsen der ganz obersten kleinen Spitze kann das Höhenwachstum ebenfalls eingegrenzt werden. Die Cannabis-Pflanze steckt dann ihre Energie in die Bildung von zwei anstatt einer Triebspitze. Wird dies nach einiger Zeit nochmal weiter oben wiederholt, entstehen an den zwei Triebspitzen dann nochmals jeweils 2, also insgesamt 4 Triebspitzen. Macht man dies ein weiteres Mal, kommen am Ende 8 Triebspitzen raus. Wie oft dies wiederholt wird und ob, hängt davon ab, welche Form man am Ende bei der Pflanze haben möchte, also auch von der Anbaumethode. Durch Topping wird die Pflanzenhöhe reduziert und das senkrechte Wachstum limitiert. Topping sollte erst vorgenommen werden, wenn die Pflanze bereits einige Wochen alt ist, schon viele Wurzeln gebildet hat und mindestens 10-15 cm hoch ist. Es kann auch gemacht werden, wenn die Pflanze schon höher ist, dann „teilt“ sie sich eben erst weiter oben in zwei oder mehrere Hauptstämme. Wichtig ist auch, das Topping mindestens eine noch besser 2 Wochen vor Umstellung zur Blüte vorzunehmen. So hat die Pflanze noch ausreichend Zeit, um sich von dem Stress zu erholen und neue Seitenzweige zu bilden. Wenn man einen größeren Teil des Haupttriebs kappt, bei einer bereits höheren Pflanze, kann man aus diesem locker einen sehr guten und kräftigen Kopfsteckling machen und hat so noch eine weitere Pflanze. Man geht dabei genauso vor wie bei Stecklinge selber machen beschrieben.

Einen richtig dicken Headbud haben Pflanzen, die nicht getoppt wurden, also die man nicht oben abknipst. Allerdings hat man bei den ganz großen Headbuds und Blüten, so schön sie sind, auch ein erhöhtes Risiko, dass besonders gegen Ende der Blütezeit, dann plötzlich Botrytis auftritt. Die riesigen, sehr kompakten Buds enthalten Feuchtigkeit, die nicht rechtzeitig genug durch Luft abtransportiert werden kann und so entsteht dann die Gefahr, dass sich Schimmel bildet. Wird der Headbud „gespreaded“, also durch das Topping mehrere Triebspitzen erzielt, erhalten die einzelnen Blüten im obersten Teil der Pflanze somit auch mehr Licht und es kann unter Umständen dadurch zu einer Ertragssteigerung kommen.

Wuschel monster - Thinning out leaves and branches

Some cannabis plants grow extremely fuzzy and bushy. They use a lot of energy to grow and form a real labyrinth of side branches. Outdoors, these monster bushes can produce very large yields, but they are poorly suited for indoor use. Because the plant energy is distributed and subdivided in an infinite number of directions, very many, but only smaller flowers grow. The individual flowers get less light because of the extremely bushy growth, and the air flow between the leaves, branches and buds is less possible, so fungal diseases or pest infestations can occur more easily and then spread accordingly. If pest infestation occurs, it is correspondingly more difficult to combat due to the large amount of leaf material.

It is important to note that not every plant with a bushy growth habit is a fuzzy monster that must be pruned. However, for some varieties, cultivation methods and, above all, limited space, it can be advantageous to a reasonable extent.

Thinning out when growth is too bushy

To prevent a fuzz monster and optimise the productivity of the plant, carefully choose which branches are suitable as producers of large flowers and which should be removed. The number of side branches that should grow out fully should correspond to the available growing space and the size and strength of the root system. In addition, if the growth is too bushy, it is usually a good idea to remove the excessive number of small leaves (but never all of them, approx. 1/3) so that more light reaches the flowers. Also cut off with a clean cut at the base.

Avoid excessive pruning

Excessive pruning causes stress to the plant and should therefore be avoided. You should always have a good reason for pruning a plant. Because of pruning, it has to expend energy to heal itself, which at the same time robs it of energy for other processes. Prune only what makes sense and only as much as is necessary.

Pruned branches and shoots are susceptible to being attacked by diseases, fungi or insects at the cut. It is recommended by some growers that tree sealant be applied to the cut surfaces. However, scientific research has shown that this is mainly a cosmetic product that may slow down the healing process. You can use it, but it is not said that it really makes sense or is better. In any case, keep an eye on cuts and immediately if you suspect a fungal infection, cut the area away widely and apply fungicide.

The less stressful option for the plant with less risk of infestation is super-cropping, where branches are bent and the cells squashed but not cut. See more at: Super-cropping. Then the limp, cropped branch is left hanging for a few days so that the wound can heal first and then it is cut off. This takes a little longer, but is gentler on the plant.

Tool/material for trimming

• Scalpel
• Disinfectant for surfaces (for the scissors or scalpel)
• Gardener's shears