Training cannabis plants during the vegetative stage is certainly one way to enhance production. Another way is through pruning, which is the art of removing selected lower growth in order to maximise the growth energy of the plant. Below I explain the advantages of pruning, why it is done, when it is done and how to correctly prune a cannabis plant step by step.
What Is Pruning?
Pruning cannabis plants is a way to manipulate the growth structure of the canopy. Allowing a grower to choose where the remaining growth energy will dominate. Similar to how the fimming technique causes lower shoots to grow bigger, pruning will allow the upper shoots to grow which are the most desired flowering sites.
A good way to think about the advantages of pruning is to compare the gym routine of a bodybuilder. When training, a bodybuilder will cut out cardio and will ensure their post workout involves no sauna or steam treatments. The reason is in order for their muscles to retain the most water content and to use 100% of their energy output on one particular body part each visit.
Essentially this is what pruning does to the plant. Allowing them to bulk up and focus 100% of their energy on growth. Many growers feel this is the most efficient way to grow and comes with many benefits.
The Benefits of Pruning Cannabis Plants
There are a number of benefits associated with pruning cannabis plants. As mentioned above, converted growth energy is just one. Other advantages of pruning are the removal of any low grade, popcorn bud, as well as an improved air flow around the base and middle of the plants.
Not only will this improve the levels of fresh CO2 rich air the plants will use, it also means pests, bugs and other unwanted guests will struggle to burrow in lower undergrowth as it will be non existent. Pruning cannabis promotes thick, larger sized buds that once dried have a size of around 2-3 inches and will have maximum bag appeal.
As well as an improvement with overall bud structure and flower density, there will be an increase in total yield. This is in comparison to if you grew the same strain that was not pruned and left to grow naturally. Pruning on a large scale can take some time, however is far less laborious and time consuming than other methods of plant training such as L.S.T, fimming and Scrogging.
When Is The Right Time To Prune
Pruning should be performed at the latest stage of the 18/6 period. Just prior to the flowering stage. It is during this time the plants will stretch up to the lights and prepare to grow a top heavy canopy of buds.
Indica dominant varieties can require pruning early on during the growing phase. This is to remove thick fingered, wide fan leaves that will block light, precious air flow and promote a breeding ground for pests.
You should have an idea how much of the plant’s foliage can be removed, based on the length of time the plants spend under 18/6. For example, if you are growing from seed and have 4 weeks of vegetative time. Then there is only so much pruning you can do compared to a plant that has grown to a large size.
Never prune once you have passed the 2 week mark of the flowering cycle. Removing solid growth may be counter productive and cause stress to the plants.
What Parts Do I Remove?
The rule of thumb is to leave the top 2 internodes of each branch. So, by counting the top 2 nodes and stripping away everything from that point, the prune is complete. As you want each branch to produce top heavy buds, the trick is to then prune each branch symmetrically.
At first it will seem like you are butchering your plants. However, removing around 75% of the original foliage will pay off. The remaining 25% will receive all of the intense lighting and 100% of the plant’s growth energy. This means the energy is focused on flower and not foliage.
After successfully pruning your plants, you will have a bag of fan leaves, soft wood shoots and undeveloped growth sites ready to dispose of. This may be a good time to keep the removed parts as clones for a later project or as a mother plant.
What Do I Need?
With experience, pruning can be done with the finger and thumb. If you are new to this technique then it is best to use a pair of sterile, sharp scissors or a scalpel. You will aim to remove the selected foliage as cleanly as possible. Avoid tearing the plants. You want to leave any remaining growth and produce the smoothest cut possible.
After the initial prune is completed, you will need to remain vigilant and look for any new growth tips. This is only natural and with a finger and thumb can remove any soft growth over the upcoming days.
Pruning: Step By Step Guide
Once you have selected the cannabis plant to prune, find a space that you can easily work in. Then prepare your scissors or scalpel and ensure they are clean.
Carefully cut away, as cleanly as possible, any fan leaves and lower shoots. Start below the 2nd internode from the top of the branch.
Work on each branch until the the only growth remaining is above the top 2 internodes of the side branches and main cola.
Carefully dispose of the cutaway fan leaves and smallest growth. Any good sized shoots can be kept for clones.
Once you have stripped away 75% or more of the foliage, you can now place the plants in a flowering room so they can receive 12/12.
Top Tips On Pruning
- Always prune your plants during the growing phase under 18/6 lighting.
- Deter any new growth every few days by rubbing the stems with your finger and thumb.
- Avoid any other plant training after pruning such as topping, tying down and fimming.
- Make sure your scissors or scalpel are clean and sterile when removing foliage.
- Use discarded lower shoots to make clones .
- Some strains may react better to pruning than others, depending on your set up.