Mainline and manifold training are techniques to grow plants with eight main colas rather than one. Both techniques involve strategically topping the plant multiple times to produce a symmetrical structure. Mainlines and manifolds are possibly the best ways to train cannabis plants. The benefits of mainline and manifold training include symmetrical colas, excellent lateral branching, and an efficient plant structure.
In this article, we explain the fundamentals of mainline and manifold training for cannabis plants. To begin, we define what is a cannabis mainline and what is a cannabis manifold. We then explore the benefits of mainline and manifold training from the perspective of plant science and compare them to other popular training techniques. Finally, we compare mainlines with manifolds to help you determine which is the best training technique for your cannabis grow.
This article is part one of our comprehensive guide to mainline and manifold training for cannabis plants.
The Coco for Cannabis Guide to Mainlines and Manifolds
- Mainlines and Manifolds: The Best Ways to Train Cannabis Plants
- How to Mainline Cannabis Plants
- How to Manifold Cannabis Plants
- Training Mainlines and Manifolds in Late Vegetation and Flowering (Coming soon!)
Cannabis Training Terminology
In these articles and tutorials, I use the terms "topping", “node”, “growth tip”, “top” and “cola”.
Topping the plant is cutting off the top of the stalk. This removes the apical growth tip and redirects growth to the lower branches on that stalk. To learn more about the science and practice of topping, see our tutorial, "Topping Cannabis Plants: Why, When & How".
A “node” is a juncture on the stalk of the plant where a new branch will grow. A “growth tip” is a small developing branch that forms at each node.
Early in life, cannabis plants grown from seed produce symmetrical nodes with a growth tip and a fan leaf on each side of the same node. When we count nodes, we start with the first true set of serrated leaves and count up.
In mainline and manifold training, we often remove growth tips before they have the chance to develop into much of a real branch. When they are small we usually refer to them as “growth tips”, but “growth tips” that are left on the plant will become branches. The main branches that reach the canopy are called “tops”. This is literally because they reach the level of the top of the plant. During the flowering stage, the branches that are tops will swell with flowers and are referred to as “colas”. One of the main benefits of mainline and manifold training is that they produce cannabis plants with lots of colas!
What is a Cannabis Mainline?
The term “Mainline” for cannabis training is credited to the grower “Nugbuckets”, who popularized the basic technique. Nugbuckets tops his plants three times to produce plants with eight equal colas. His basic topping strategy defines a “Cannabis Mainline”.
Cannabis Mainline: A plant that has been topped three times at symmetrical nodes to produce eight equal main branches or “colas”.
What is a Cannabis Manifold?
The term “Manifold” for cannabis training is credited to the grower “Nebula Haze”, who modified Nugbuckets’ mainline strategy. Rather than topping the plants three times, her technique produces eight nearly equal branches after only topping it twice. Because it skips the third topping, it is moderately faster to accomplish. However, it is less symmetrical and generally only saves about two or three days compared to a full mainline.
Cannabis Manifold: A plant that has been topped twice. Two branches are preserved during the first topping. Four branches are preserved from each side during the second topping, which leaves eight nearly equal main branches or “colas”.
Both mainlines and manifolds are excellent training techniques for indoor cannabis. Each technique offers slight advantages in different situations. However, before comparing the different training techniques, I want to review the benefits of mainlines and manifolds and explain why I consider them to be the best ways to train cannabis plants.
The Benefits of Mainlines and Manifolds
In my opinion, mainlines and manifolds are the best ways to train indoor cannabis plants. They produce large well-balanced plants and an even canopy. Mainlines and manifolds are easy to train and manipulate during the vigorous growth of the stretch. Pulling the main branches outward opens opportunities for lateral branches to fill in the canopy. Mainlines and manifolds can grow to be as wide and broad as the space available. I train all my plants as mainlines or manifolds.
In our article, “Why You Should Train Cannabis Plants” we explain the benefits of encouraging plants to grow out horizontally rather than vertically. A broad and even canopy helps to make the most efficient use of the light, which increases the size of the harvest. Mainlines and manifolds are possibly the best way to achieve the desired growth shape and canopy coverage.
Mainlines and manifolds produce plants with several “tops”. The eight main branches all become their own “top” and lateral branches from each of them can also reach the canopy and become “tops”. This distributes the resources and the energy of the plant more efficiently and produces many colas rather than just one. As a result, these techniques produce a large yield of the most desirable buds.
Several Colas Are Better Than One
Some grower’s desire that one large single cola from an un-topped plant. It looks appealing; however, it is not an efficient structure. Furthermore, very large colas are much more susceptible to bud-rot, which can cost you your entire harvest. It is more efficient and safer to split the dominance and grow many top colas with a mainline or manifold.
The benefits of mainlines and manifolds come from the structure of the plant itself. Both mainlines and manifolds grow from a single node on the main stem. This produces several significant benefits in terms of overall growth.
Nugbuckets and Nebula Haze both stress the fact that the symmetrical stalk structure serves to equally distribute resources up from the roots to the different parts of the plant. This may be true; however, it is not the most significant benefit from the single node structure. The main benefit from growing plants through a single node is that it completely changes the apical dominance of the plant.
Mainlines and Manifolds Change Apical Dominance
As we explain in our article, “Topping Cannabis Plants: Why, When & How”, there are plant growth regulating hormones in cannabis called auxins. Auxins are produced in the top growth and flow downward through the plant inhibiting the growth of the lower branches. They are responsible for the classic “Christmas tree” shape of an untrained cannabis plant.
The growth inhibiting effect of the auxins is dramatically reduced by mainline and manifold training. Topping the plant removes the apex which had been inhibiting the growth of the branches on the third node. Those branches become the new “tops” and assume dominance in growth. We remove the lower branches on the main stem because they would be inhibited by auxins from the third node. The only two branches that remain grow from the same node at the same height. This leads to the two branches becoming co-dominant because neither can inhibit the growth of the other.
Topping the plant for a second and third time further continues this process of dividing apical dominance. Mainlines, which are topped three times, divide apical dominance and the flow of auxins better than manifolds, which are topped twice. However, topping a cannabis plant more than three times does little to further divide the dominance.
Both mainlines and manifolds will allow you to grow as many “tops” as you have space for without further topping. You can simply allow the side branches from the eight mains colas to become additional tops. Since the apical dominance is already well distributed, all the branches that receive light will grow without inhibition.
Mainlines and Manifolds are Good for New Growers
Mainlining and manifolding are systematic training techniques that are easy to accomplish even for new growers. You need plants that are growing well, courage and trust, but it requires no special skills. You can simply follow the step-by-step instructions in our Mainline and Manifold Training tutorials.
The Challenges of Growing Mainlines and Manifolds
The biggest challenge with mainline and manifold training is to get the plants healthy and growing quickly. You should never top a plant that is struggling, so if the plants struggle early it can delay or prevent mainline and manifold training.
The medium that you grow in makes a considerable difference in how long it takes to complete mainline and manifold training. In coco coir with high frequency fertigation, manifolds can be complete in less than four weeks and mainlines can be complete in less than a month. In soil, the time needed to complete training for these techniques is six to eight weeks.
The Best Ways to Train Cannabis Plants
Mainlines and manifolds allow plants to grow horizontally and create an even canopy. However, they are not the only ways to train cannabis plants to grow horizontally or otherwise fill the canopy. Many growers use a “screen of green” (Scrog) to train their plants to be low and wide. A very different alternative is to grow a lot of small plants in what is known as a “sea of green” (SOG). These are both appropriate plant training or management strategies in different situations. However, for most growers, I believe that mainlines and manifolds are the best ways to train cannabis plants.
Mainlines and Manifolds Vs. A Screen of Green (Scrog)
A “Scrog” uses a screen that growers lay over the plants. As the plants grow up and through the screen the grower bends them back down and uses the screen to restrain them. In this fashion, a plant can be trained to grow out horizontally to cover a large area.
Scrogging helps to spread the plant out, however, it can limit the canopy depth. In a scrog, the plant is held at the height of the screen as it spreads out. In contrast, mainlines and manifolds grow up and out at the same time. This produces a broad even canopy with good depth to each cola. A canopy full of tall dense colas is the best way to maximize the quality and the quantity of the harvest.
Mainlines and Manifolds Vs. A Sea of Green (SOG)
The other popular strategy to get a canopy full of tall dense colas is a “sea of green” (SOG) (See our Sea of Green Tutorial). A sea of green uses a high density of plants with no training and short vegetation times. As we explain in our Sea of Green Tutorial, it is an excellent strategy for growing. However, a SOG is not a plant training technique, it is a grow management strategy.
Mainline and Manifold training require a longer vegetation period than a SOG grow but they use far fewer plants. In a 4x4 grow tent, a SOG grow could use 16 or 25 plants and only a 1-2-week vegetation period. With mainlines or manifolds you can fill the same tent with only 2 to 4 plants and vegetation times of 5-6 weeks.
Which Is Better? Mainlines vs Manifolds
I regularly use both techniques to train different plants. I prefer the shape and symmetry of a mainline, but there are situations where manifolding makes more sense. To determine whether you should mainline or manifold your plants, consider the relative merits of each.
Mainlines are More Symmetrical than Manifolds
Mainlines are topped three times to produce eight branches. None of the branches can inhibit the growth of the others because they all emerge from the same height on the plant. This leads to a plant with eight equal branches that all become their own “tops”. It is easy to maintain the symmetry of a mainline plant by simply ensuring that all eight branches or “colas” have equal access to the light.
A Manifold is topped twice rather than three times. Two toppings greatly reduce the apical dominance that the plant will exhibit. However, after growing the first two branches from a single node, a manifold has branches on different nodes. This creates an opportunity for the higher branches to suppress the growth of the lower branches with auxins.
Although they are smaller at the time of the second topping, the branches on the third node are higher on the plant than the branches on the first node. As a result, they will produce auxins that will flow downward and inhibit the growth of the branches on the first nodes. Because of this, manifolds tend to grow larger branches on the ends and smaller branches in the middle. This can be controlled, but manifolds require continued training to promote equal growth among the eight main branches.
Manifold Training is Faster than Mainline Training
The main advantage that manifolds hold over mainlines is that they can be completed slightly faster. Both training processes are largely the same up until the second topping. After the second topping a manifold is done, but a mainline still has one more topping to go. The difference in time required to complete the toppings for a manifold versus a mainline is small but it might be significant.
For most plants, completing the topping faster is not a good reason to choose manifolding over mainlining. When plants are growing well, it often takes only two or three days between the second and third topping for a mainline. Furthermore, mainlines grow better during the stretch and will end up ahead of their manifolded sisters.
The Best Way to Train Different Cannabis Plants
Because of the relative benefits of mainlines and manifolds, they are each suited to different types of cannabis plants. I recommend Mainline training for photo period plants grown from seed. However, I think that manifolds are more appropriate for clones. I also manifold auto-flowers… Yes, you can manifold auto-flowers!
Mainline Training for Photo-period Seeds
I recommend mainline training for photo-period cannabis plants grown from seed. Plants grown from seed have excellent symmetrical nodes through their early growth. This makes it easy to mainline and maximizes the benefits of the symmetrical repetitive topping. Photo-period plants can be kept in vegetative growth for as long as it takes, so there is no need to prioritize the slight advantage in speed that is provided by manifold training. The symmetrical growth and lack of apical dominance will more than make up for the slight delay in completing the topping. See our Tutorial, “How to Mainline Cannabis Plants”.
Manifold Training for Clones
Mainline and manifold training for clones is more difficult because clones grow without symmetry. Early in life cannabis plants produce symmetrical nodes with two branches that emerge from every node at the same place. However, as the plants mature, the nodes lose their symmetry and the branches emerge at different points on the stalk. Since cannabis clones are usually taken from mature plants, they also have asymmetrical nodes. This makes it a challenge to top the plants and produce two equal branches.
Clones can still be mainlined or manifolded, however, because there is a lack of symmetry, there is no real advantage to a mainline. It is easier and more productive to simply manifold clones. I cover the special steps that you must take when you manifold clones in our tutorial, “How to Manifold Cannabis Plants".
Manifold Training for Auto-flowers
There are a lot of rumors that auto-flowers should not even be topped once let alone several times. However, the rumors are clearly not always true. Auto-flowering cannabis plants can be topped and they can be manifolded. They could even be mainlined, but this is the one time when the couple additional days required for mainline training might make a difference.
In order to manifold an auto-flower you need to get it growing quickly. Cannabis plants should not be topped once the plant has entered the flowering stage. Most auto-flowering cannabis strain will begin flowering by the fifth or sixth week of life.
In coco/perlite with high frequency fertigation, many growers will be able to get the plants growing fast enough to top them twice and make a manifold before day 30. This is not usually possible in soil grows. However, as long as the second topping is completed before the plant starts to produce flowers then it will recover well and generate the benefits of a manifold. I give advice about how to manifold auto-flowers in our tutorial, “How to Manifold Cannabis Plants”.
Mainline or Manifold Your Cannabis Plants!
This article is just the beginning. We have step-by-step tutorials to guide you through the mainline or manifold process.
Once the structure of your plant is complete be sure to read our tutorial, “Training Mainlines and Manifolds in Late Vegetation and Flowering” (Coming Fall 2022!)
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