The Cannabis Grow Bible
by Greg Green
Many a marijuana cultivator have taken a pair of clippers to the top of their plant just above the last branch formation during the 3rd or 4th week of vegetative growth. The top is removed by shearing it away at the stem. This can also be done during the thinning stages. What happens next is that the main stem may split off in two or more directions. This creates a V shape at the top of your plant. The end results after flowering are two or more top colas instead of one. Now, many a cannabis grower will tell you that this is a great thing to do and sometimes it is. Two top colas instead of one does sound appealing but alas it must be said that this TOPPING method of pruning does not always work out the way you think it will.
Sometimes the plant will produce two small top colas instead of two big ones. This really depends on the strain and the environment. Many a grower have managed to bring a plant into growing more than six top colas by this method. Each strain will have a threshold for bud production, which can not be improved on. Some plants when grown fully without pruning do not reach their threshold. The strain Blueberry is a good example of this. If you grow blueberry without topping you will not achieve maximum bud production from that plant, but if you do top the blueberry you will. Other strains are not so flexible and by topping you will not increase bud production. The two top colas will simply be sharing the same volume of bud that a single cola would have produced on the same strain. So pruning for production is strain related and grow related. You need to find a strain that responds well to topping.
It is advised that you experiment with this pruning method. Do this with 2 out of 10 females with every grow you do. You will find in time that during this vegetative prune you will be able to shape your plant. Plants are generally pruned 3 – 4 weeks into their vegetative cycle but can be pruned sooner or later or more than once. Pruning during flowering will cause problems with bud production because the plant will divert its energy from bud production into branch and leaf production. The results will be a slower rate of Bud growth.
Remember how we spoke about Indica plants being small and Sativa plants being tall. Well if you learn to prune your plant right you can generate small bushy Sativa plants that grow in tiny spaces. Without pruning the Sativa plant it will probably stretch to five feet and more.
For every stem or branch you prune, the cut area will develop two more branches. Look outside at any tree. See how the stem divides into branches which sub-divide into more branches which divide into new shoots and leaves. Well some marijuana plant only grow a main branch out from the stem and this may stay that way throughout its entire grow. Any filling out usually occurs when new leaves and branches develop at the nodes. Some lateral branches may develop new shoots but these are somewhat small and thin and do not support much bud growth. If we prune our plant we can make it more like the tree that we see in the garden. There is also a limit to how much we can prune. Let us follow a prune path for a moment.
If we prune the stem, it will split into two. We can prune both these two new stems and end up with four stems. We may try to prune each of these four stems to try and create eight stems, but this depends on the strain and its branching limit which is genetically based. We may be able to prune some of the lateral branches but again if the plant has reached it threshold it will not produce more new branches. All strains are different in this respect.
Prune cuts are made using clippers at a 45-degree angle to the shoot being cut.