Cannabis topping is a plant training method that changes the morphology of the plant and increases the quality and the quantity of the yields. It allows cannabis plants to get more light and grow more buds. It’s a very popular technique used by a large number of growers around the world.
In order to top your plants the right way, it’s crucial to know exactly when to top cannabis. If you mistime topping your cannabis plant you can damage it severely or you can simply miss out on getting the most out of this method.
However, to understand what’s the best time to top cannabis and why, first you need to know what topping exactly is, how it’s done, why it’s done, and what its main benefits are. So let’s start.
What is cannabis topping?
In the simplest of terms, topping means cutting off the very top of the main stalk of a marijuana plant. It’s usually cut above the 4th or 5th branch, and this results in getting basically two thinner main stalks that grow further. You can repeat this process multiple times during the vegetative stage.
It can be done by different cutting tools, and it’s best if these tools are disinfected so that you prevent any possible infections in the plant. It’s also great if this tool is as sharp as possible so you can make a truly clean cut. But some growers think these precautions are unnecessary so a lot of them just use their fingers to remove the top shoot.
So topping is not the same as pruning, although it’s a bit similar, since you’re cutting off parts of the plant that prevent it from fully developing. But pruning means removing branches and leaves that are either too far away from the light or already dead so that the other parts of the plant get more energy. Topping is different since you only remove the top branch, and it has very different and very interesting consequences for the plant.
Consequences of cannabis topping
The main consequence of topping is a gradual change in the plant’s morphology. Instead of having a recognizable, natural “Christmas tree” shape, it keeps the plant wider and flatter. Cannabis starts growing laterally, gets bushier, and slows down its vertical growth. There are three reasons why this happens:
1. Topping diverts growth hormones and energy from the top of the main stalk to lower branches. The plant also recognizes topping as a stressful event so it starts supplying these lateral branches even more intensively as an answer.
2. The apex of the plant actually contains Auxins, hormones that are responsible for the plant growing vertically instead of bushing out, which is called apical dominance. This hormone is produced in the top part of the main stalk and sent downwards to inhibit lateral growth of the lower branches. Once you remove the top, the production of this hormone basically stops.
3. The third and the simplest reason why cannabis branches out after topping is that one main branch on the top is replaced by two branches that start growing wide. As we mentioned, you can top these two a few more times in order to make the plant grow out further.
Why is topping important?
Now that we know that the effect of topping is branching out and increasing lateral growth at the expense of vertical, we should ask the question why would you even want this. There are at least three main reasons why growers choose to top their weed.
1. Distribution of hormones and energy
First and foremost, by redirecting hormones and nutrients to lower branches, the plant achieves a much better distribution of energy that simply brings better yields. When left to grow on its own, a marijuana plant focuses its efforts on the main stalk and one giant cola that grows on it. The other colas are then often small and less developed.
With topping, you make the development of the plant more even, which creates more bud sites and makes for a better output. The two main stalks are individually not as strong and powerful as the single natural main stalk that you cut off, but when you combine these two they can get you more high-quality buds.
Also, you’ll get a stronger plant overall. As soon as you remove the top, you’ll see certain changes – the connections between branches will thicken and the whole plant will become tougher and more durable. This way the plant facilitates the flow of energy and hormones, especially after getting into the mentioned recovery mode as a consequence of stress.
2. More sunlight for the lateral branches
It’s vital to mention that topping is mostly an indoor growing technique, and for a good reason. Namely, the shape that marijuana plants take naturally is the one that most fits their natural environment. The Christmas tree shape suits the circumstances perfectly, as all the branches will get enough sunlight during the day as the sun “moves” through the sky, evenly delivering light to different parts of the plant.
But in an indoor setting, things are different. There’s usually just one source of light from above that doesn’t ever move. So the lower branches often won’t get enough light if you don’t use tricks such as topping to induce lateral growth.
Basically, by removing the top of the plant, you make the low branches grow wide and avoid getting blocked out by the higher branches. This way they’ll get more light and you can even extend the vegetative phase of their growth.
3. Height management
Finally, one of the reasons why topping is performed is to manage the height of the plant. For indoor growers that don’t have much vertical space for their cannabis, the fact that they can basically control the height can be very valuable.
Outdoor growers can profit off of this as well. Sometimes marijuana plants can go really high up and, well… attract attention. For those who don’t really want to make it too public that they’re growing weed, it can be useful to have shorter, wider plants.
When to top cannabis?
At last, we come to the main question of this article – when is the best time to top cannabis? Now that you already know a few things about topping, it’s much easier to explain the best timing for this training method.
Mind the overall plant health
First of all, you should remember that topping can be a very stressful event for the plant. There are a number of criteria for determining the right time for topping, but the key one should be whether the plant is healthy and strong enough to sustain this trauma.
So apart from making sure that the plant gets enough water and light, and grows in top-quality soil, you should also make sure that it has developed a strong root system. This is necessary so that the plant can quickly recover from topping.
In any event, you’ll want to do this sometime in the vegetative phase of growth. If you do it in the seedling phase, the plant is still too weak and topping will severely damage it or even kill it. And if you wait for the flowering stage, it’s already too late and it won’t have any positive effect on the yield or the plant in general.
Watch the number of nodes
Saying that you should top cannabis in the vegetative phase is far from enough, as it can last up to several months. However, it’s impossible to provide a definite timeline for topping as it can be quite different, depending on the sort of weed and the environment it’s grown in.
So it’s probably better to count the nodes. There’s no consensus on this number as well – but you should top the plant once it’s developed around 4 to 7 nodes. Again, it’ll depend on the overall health of the plant and you should always wait for it to be in good condition and resilient enough to handle the damage.
In general, the trick with topping is to achieve the right balance. You don’t want to start too soon as it can seriously hurt the plant, but you also don’t want to start out too late. Being a bit late with topping won’t harm the plant though, but if you wait for too long, you won’t use all its potential and you won’t be able to maximize your yields.
When can I start topping again?
It depends. Again, there are various estimates made by different growers, and keep in mind that every plant is unique. It’s best to sit and wait for a bit and check how the plant is handling the stressful changes.
As always, the best rule of thumb is to start topping again when the plant is fully recovered – you can never go wrong with that. It will even be reinforced by the optimized distribution of hormones and nutrients. Some growers will tell you to wait for at least 2 or 3 days before re-topping, some will say that you should extend that period to a week or two, but every grower should test and then determine what’s best for their plants in the long run.
In any event, you can top weed as many times as you want until the end of the vegetative cycle. Just make sure you give the plant enough time to heal.
Topping vs fimming
There’s also another type of cannabis plant training very similar to topping, and it’s called fimming. In a way, it could be even said that it’s a special type of topping.
Fimming also means removing the apex of the plant, but you don’t really remove the whole thing, but rather some 75% of it. It seems messier and it probably started as a mistake. Even its name means “f*** I missed”, but then, the person who missed realized that this different kind of topping also brings numerous benefits.
Somewhat surprisingly, fimming produces even more new main branches than topping. While topping creates only 2 new shoots at the top, fimming can create anywhere from 3-4 to 8 or even more.
However, there are different downsides to fimming when compared to topping. It’s not really as effective as topping and it usually takes more time for a plant to recover from fimming. Moreover, some strains may not be able to withstand constant fimming and too many buds will be too heavy for strains with weaker branches. Also, sorts with shorter internodes may end up with a canopy too dense which can block the light and prevent air circulation.
Final thoughts
At the end of the day, it’s really all about balance and recognizing the needs of particular strains and plants. We did present some useful guidelines about when to top cannabis and how often, but you’ll always have to take many different factors into account.
Not everyone has to top their cannabis plants, but if you decide to do this, make sure that the plants stay healthy and strong throughout the process. Always give them enough time to develop or recover and don’t expect impossibly high improvements in yields. If you push the plant too hard and demand too much, topping can only have unwanted effects and do serious long-term damage.
FAQ – topping cannabis
How to top cannabis plants?
Topping a cannabis plant simply means cutting off the top of the main stalk. It should be done above the 4th node (or higher), preferably with sharp, disinfected tools, that can make a truly clean cut.
When is it too late to top my cannabis plant?
The flowering stage is already too late. You can top it at any time while they’re still in the vegetative stage, but if you do it afterwards, it won’t have any effect on their further growth and you’ll just be unnecessarily damaging the plant.
When to stop topping cannabis?
You should stop doing it once it reaches the flowering stage as the plant is not growing anymore but only producing new colas or stems. Also, if you see that the plant is not handling topping too well, you should stop for a while and give it some more time to heal.
How often to top cannabis?
In theory, you can do this as often as you want, but if you do it too often, it’ll probably damage the plant. Some growers say you should wait a week or two between two separate topping events, while others claim that a few days is just enough. It really depends on the strain and growing conditions.