Whether an amateur or experienced cannabis cultivator, having the knowledge and skill of one or more marijuana training techniques is essential. Using techniques such as topping cannabis plants involves manipulating them to grow in specific shapes, patterns, sizes, and directions that they usually wouldn’t. By doing so, you get to speed up the growth period, harvest better yields, and make your work easier by working with plants with manageable sizes. Also, training plants ensure there is an equal distribution of resources, such as light, heat, and airflow. By creating uniformity in the growing environment, you deter the thriving of pests and diseases.
Topping cannabis is considered a high-stress technique that involves intentionally cutting off the dominant stalk of the plant. Looking at an untrained cannabis plant, you will notice that as it grows, it tends to take on a shape similar to a conifer or Christmas tree (inverted ‘V’ or like a triangle). This is because the apex is exposed to more light than the rest of the branches, giving it the advantage to grow taller and produce better yields. This, however, is not ideal as the rest of the plant produces less than optimum yields, which means your overall yield is not up to standard.
Once the apical dominance is eliminated, other branches are exposed to sufficient light. They produce more branches, leading to healthier plants and double the yields. Looking at a topped plant vs. non topped plant, you will notice that the former is broader and bushier as it grows laterally instead of the traditional vertical growth. Topping can be done to indoor and outdoor plants, although the choice to top is based on the type of weed strain and the situation (more of this later).
Now that you know what topping is, you probably have a series of questions, such as when topping is done, how to do it, what strains to top, mistakes to avoid during topping, and how to treat the plant after topping. This comprehensive piece will answer all these questions. So, without further ado, let’s begin…
When to top cannabis?
Understanding the marijuana plant’s growth cycle is vital in determining the best time for topping. You need to pick a time when the plant is strong enough to recover from the traumatic experience (yes, having a part of it cut off changes its physical appearance and chemical composition). The recommended time for topping is 30 days after germination, as the plant enters its 5th week of growth (vegetative stage).
This, however, is not standard as grow environments and cannabis species differ. An ideal time for one plant may not be for another plant. Additionally, the health condition of the plant is something to consider. Is the plant exposed to optimum light, temperature, air, and humidity? Is the soil’s water, nutrients, and PH level optimum? Is the plant battling diseases or pest infestation? Topping a plant already battling deficiencies, diseases, or growth issues may lead to negative results. Ensure that the marijuana plants are healthy and subjected to optimum conditions before initiating the High-Stress Technique.
During the 4th or 5th week, cannabis plants will have grown 5 or more nodes. This is considered the ideal time to top your plants. Topping too early will lead to stunted growth and an extended vegetative stage. When you top your plants too late, the energy the plants have used to grow vertically will go to waste instead of being focused on lateral growth. So, how many nodes before topping? Target the stem right above the 5th node. The plant can comfortably handle the shock of topping and resume normal growth at this growth stage.
What is a node? This refers to the junction where the branches grow from the main stem. In a cannabis plant, the nodes occur in pairs. The space between one node and another is called ‘internode.’ Sativas tend to grow very tall, so you will find that their internodal distance is longer than that of Indicas or Ruderalis species.
Importance of topping marijuana plants
You might be wondering, what is the importance of topping cannabis plants? Is it necessary?
Topping is not meant for all cannabis strains or every situation. You will find that some plants will benefit from topping, while others won’t. In other instances, the plants will require training but not necessarily topping. Below are some of the reasons and benefits behind cannabis topping.
Limit plant height
When the central bloom is cut off, the plants tend to form a flatter canopy that focuses their energy on growing horizontally. Vertical growth is limited, which significantly reduces the plant’s height. This is especially true for Sativa strains that grow up to 4 meters tall. This technique is recommended if you cultivate marijuana plants in an environment with limited vertical space.
As the plants grow laterally, more branches are formed. Instead of light and other resources being focused on the terminal branch, they become evenly distributed, leading to faster growth rate, healthy plants, and ultimately, better yields.
Shorten the growth period
Once apical dominance is subdued, the plant experiences exponential growth, shortening the vegetative stage.
What you need to know about apical dominance
As highlighted earlier, when cannabis plants are grown without training, the apex dominates by growing and budding at the expense of other branches, resulting in less than ideal buds. This is because the apex produces a growth hormone – auxins- that inhibits the elongation of the branches below it. The hormone is transported through the phloem but only travels a short distance. As such, only the branches near the apex get to experience growth inhibition.
As the plant grows taller, the Auxins stop reaching the branches on the lower parts of the plants. The branches start developing, which ultimately ends with the plant taking on a conifer or triangular shape. By breaking the apical dominance, all the branches get a fair chance of growth, leading to an accelerated growth rate.
Make cannabis plants easier to work with
Working with plants of a 3-5m height can be a difficult task. By limiting vertical height, you make the task of monitoring and caring for your plants simpler.
Training a plant to become a mother plant
Have you ever wondered where cannabis clones come from? A cannabis mother plant is a healthy variety with top genetics specifically grown to produce clones. It stays in its vegetative stage, and topping is used to control its height and allows for new growth shoots used as clones.
Topped plant Vs Non topped plant
Topped plant in veg stage
The image below shows an indoor grow after topping the cannabis plants. As the plants are not yet in flowering it is difficult to see the full impact, but the image below this shows how the number of bud sites has grown when comparing a topped plant vs non topped plant.
Topped plant in flowering stage
Now that the plant is in full flower you can see the numerous bud sites that have developed as oppose to growing conventionally which would normally only produce one main cola. Topping cannabis plants early on allows multiple colas to grow on one plant resulting in huge increases in bud production. Used correctly and this growing technique can double or even triple your yields when comparing topped plants vs non topped plants. So for any cash croppers wanting to experiment with their growing skills this is definitely a technique worth trying.
Non topped plant grown outdoors
Here is a sativa dominant plant grown outdoors, although the plant is not yet in full bloom you can see from the shape alone the difference between a topped and non topped cannabis plant. Left untrained cannabis plants will grow tall, and sativa dominant strains like the one pictured below will grow very lanky with one main central cola. The yield from this may still be decent if grown outdoors with plenty of room, however anyone limited on space or growing indoors will be better off training their plant to make best use of the space and to optimize bud production.
How to top cannabis plants
Topping cannabis plants is a straightforward process done by experienced and inexperienced cultivators alike. It is simpler, less complicated, and more convenient than other methods like SCROG, supercropping, and fimming (discussed in detail below). Here is how to top your cannabis plants;
You will need;
- Sharp razor blade or horticulture scissors
- Rubbing alcohol
Step 1: Take the cutting apparatus (razor blade or horticulture scissors) and sterilize it with rubbing alcohol. The tools are probably clean, but why take the chance of infecting your cannabis plants? Ensure that the selected tool is very sharp to avoid a rough cut. Precision is key to a successful topping procedure.
Step 2: locate the 5th node on the plant and make a precise cut. Ensure that you do not cut or damage the shoots located between the side branches and the main stem. The shoots are expected to experience a growth spurt in the coming weeks, quickly taking over from the removed main cola.
Step 3: Observe! As mentioned earlier, topping is a high-stress technique that can be traumatic to a plant. As the plant recovers, it will need optimum growth conditions. Ensure that the light, humidity, temperatures, grow medium PH, and airflow are favorable. Additionally, the plant will be undergoing rapid growth, so ensure that it gets a constant but reasonable amount of nitrogen (essential during the vegetative stage) and other macro, secondary, and micronutrients.
Depending on the desired cannabis plant size, some cultivators perform topping more than once. If you plan to do this, wait for one or two weeks for the shoots (mentioned in step 2 of how to top marijuana plants) to grow. Doing so will result in your plants having four tops instead of one (when not topped) or two (when topped once). If you top the plant further, you will end up with 8 tops, and so forth.
Using Topping and LST together
After topping cannabis plants you can leave them to grow as they are, however to further manipulate their growth pattern many growers use LST too. By tying the additional growth shoots down in a way to encourage the plant to grow a wider and flatter canopy allows the plant to absorb even more light (see image below). Topping will force the plant to produce multiple large bud sites, if you then use LST to manipulate the new growth shoots it will allow the plant to absorb as much energy from the lights as possible. Both methods used together can be very effective at increasing yield
Best strains to top
Topping is an excellent technique for cannabis plants that tend to stretch vertically. The training method inhibits vertical growth and supports a more bushy, lateral expansion. As a result, topping is best suited for stretchy Sativa strains such as;
G-13 Haze is a legendary strain classified as one of the best-yielding Sativas. A cross between G-13 and Hawaiian Haze, this plant grows to a maximum height of 2m. The strain comes packed with THC goodness reaching a maximum of 24% and a boatload of therapeutic and aromatic terpenes. G-13 Haze is an excellent choice for topping and promises an impressive yield.
Bruce Banner 3
Named after the comic book hero, Bruce Banner 3 is a heavy-hitting Sativa dominant strain with soaring THC levels of 27%. Holding the record as one of the most potent strains in the world is no joke. Since it was created, this strain has won multiple awards since it was created, solidifying itself as a classic. Bruce Banner can grow to a maximum height of 2.1m. Topping can help tame its height, especially if the grow room has limited vertical space.
Promising a memorable high, aesthetic appeal, bountiful yields, and mouthwatering flavors, Amnesia Haze will be one strain you will immensely enjoy cultivating. The strain is a cross between Jamaican and South Asian landrace strains and boasts THC levels surpassing the 22% mark. If you are looking for a wholesome Sativa strain to grow, Amnesia Haze fits the bill. The seeds grow to a gigantic plant of 2.5m, making it an ideal candidate for topping.
With a myriad of awards attached to its name, AK-47 is one of the most reputable and highly sought cannabis strains on the planet. The Sativa dominant variety is easy to grow and is packed with THC levels of 18%. Besides the perfect balance of cerebral high and body stone, AK-47 is an excellent medical strain to relieve numerous conditions. This strain can grow as tall as 2m and would be a good candidate for topping.
Can you top autoflower or Indica plants?
Autoflowers have the shortest cannabis life cycle, usually growing from seed to harvest in 8 to 12 weeks. Consequently, it would take the plant a quarter of its life to recover from topping. Rarely would you see anyone recommending topping autoflowers. If you are looking for a technique to limit the height of autoflowers and grow a more levelled canopy (sativa-ruderalis genetics), try SCROG or LST; otherwise, autoflowers are best grown naturally.
Indicas, on the other hand, are generally short and compact plants, hence no need for vertical growth control. Even during the flowering stage, Indicas do not stretch as they tend to focus on lateral growth naturally. To boost yields, you can try LST training techniques, such as trellising or SCROG.
Topping vs other stress training techniques
Topping vs fimming
Topping and fimming are based on a similar methodology. Both involve the elimination of the main boom for better yields, even distribution of resources, and more lateral growth. With topping, you remove the entire apical tip, whereas, in fimming, you only cut off about 75% of it. In fact, fimming is a result of a failed topping attempt where someone cut off the main bloom instead of the main stem. This explains the origin of the word fimming, which is thought to be from the phrase ‘f**k i missed.’
Unlike topping, which is easy to execute, fimming requires precision as it sometimes doesn’t work. After the plant grows 5+ nodes, cut off the base of the tip, eliminating a majority of the main shoot. The process is traumatic to the plant, which may require a few days to recover. Once it does, the remaining vegetation from the main shoot will grow into 3 to 8 new stalks.
With an increased number of main blooms, the plant becomes bushier and produces increased yields. Ensure you provide sufficient support to your marijuana plants through proper trellising techniques as the plant grows more branches.
Topping vs super cropping
Topping and super cropping are both high stress training techniques that are utilized to control a cannabis plant’s height. The latter technique involves bending the stem at a 90-degree angle to redirect its growth from vertical to lateral. To bend the stem, place it between the thumb and the index finger and squeeze/pinch/bend it until you feel the plant’s tissue begin to crash.
After placing it at an angle, tie it down to discourage vertical growth. Once the plant detects injury at the bent site, it sends more energy in the area to facilitate faster healing and recovery. As a result, bud production in the area is increased, leading to better and healthier yields.
Topping vs LST
Unlike High Stress Techniques like super cropping and topping, LST involves changing the stem’s direction of growth without stressing the plant or subjecting it to trauma. The technique involves tying and bending marijuana plant stems while pliable and easy to handle. LST is best conducted during the vegetative stage, before the plants become too mature to bend without breaking.
The choice between LST and HST depends on the cultivator’s preference and expertise. Some growers prefer not to incorporate HST in their growth journey, while others consider LST complicated and too demanding. Either way, the goal of cultivating cannabis is to grow a healthy plant for bountiful harvests.
Pruning after topping and its significance
After topping your plants, expect rapid growth that will see your cannabis plants develop a bushy appearance. Healthy, dense buds are produced under optimum growing conditions. Unfortunately, dense plant prevents light penetration, unrestricted airflow, and supports hot spots. Pruning allows you to eliminate less than standard leaves and branches, which only deplete resources that would otherwise benefit the healthy parts of the marijuana plant.
Pruned plants experience better airflow, light penetration, and tend to focus their energy on producing big, impressive buds. As soon as the plants start to develop a bushy appearance, start removing small or dying branches and leaves. As you prune, utilize this chance to inspect your plants for soil issues, pathogens, and signs of deficiencies.
How to prune cannabis plants
Pruning should be conducted during the vegetative stage only. As the plant enters the flowering stage, cease the process as you may compromise the quality of the buds. To prune cannabis plants, you will need;
- Snips or pruners for the small branches and leaves
- Sheers or loopers for large branches
Ensure the tools are sterile to maintain plant health and sharp to avoid messy cuts
Step 1: Start with the heavy lifting work by getting rid of the large branches at the bottom of the plant. The bottom branches can’t get sufficient light with such a bushy plant, meaning they will likely produce non-impressive buds.
Step 2: Unlike the sun, grow lights are positioned in one position. As such, some branches and leaves will benefit from the setup, while others won’t. Inspect the plants, identify the branches that get shaded, and cut them off.
Step 3: Now that the hard work is complete, look for small, unhealthy-looking, or dead branches and leaves and prune. At the end, you are left with a less dense plant, whose branches and leaves are exposed to optimum growth conditions.
Topping helps eliminate apical dominance, giving rise to a more laterally stretched plant with better yields. The technique is easy to execute and is best suited for cannabis plants in the vegetative stage that have grown more than 5 nodes. Topping is ideal for stretchy Sativas, especially when a grower is working with limited vertical space. After topping your plants, expect rapid growth, leading to bushy-looking plants. To maximize the plants’ exposure to resources, prune the plants throughout the vegetative stage and cease once in the flowering stage.