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What is Topping?
Have you ever noticed when visiting a tree farm to pick out a live Christmas tree, the best sellers are always the ones that have that perfect pyramid shape? Of course you have! No one wants a a Christmas tree in their living room with branches that are longer than its height.
It just wouldn’t look right.
Evergreens grow the way they do because of a phenomenon called apical dominance. In apical dominance, energy is devoted to the upward growth of the central stalk or trunk of the tree toward more sunlight, and it is suppressed in its lateral offshoots.
At the top of the main stalk of the tree is an apical bud, and this bud produces a hormone called auxin that controls the development of lateral branches. If the top of the tree is cut off thereby removing the apical bud, the auxin concentration in the main shoot is depleted allowing lateral buds to grow uninhibited.
While topping an evergreen may not produce a more attractive Christmas tree, it is common practice to top and prune certain ornamental trees to create a more aesthetically-pleasing shape as well as more fruits and flowers.
Why Top Your Plants?
Cannabis is another plant where apical dominance is clearly evident. Left to grow naturally, the plants will grow tall and reach for the sun, but the lower offshoots of the plant will be shaded and not see nearly as much.
This results in a lower yield of inferior quality. Cutting off the tops of the plants during the vegetative cycle decentralizes growth in the main stalk and encourages significant new lateral growth.
In turn, more quality bud sites are produced. Likewise, lateral branches can also eventually be topped to produce even more offshoots with more bud sites.
As a growth-training technique, the ultimate goal of topping is to produce rounded, bushy plants with a bounty of bud sites. Utilizing this technique results in multiple benefits.
Tall, single-stalked plants are less stable and may require supporting structures, whereas bushier plants will require less support. Additionally, because sunlight is so essential to the production of stems and leaves that are needed to gather energy for even more growth, cannabis plants that are wider than they are tall are more likely to receive a more even distribution of sunlight.
This even distribution also helps to protect the plants from bud rot.
How to Top Cannabis Plants
Topping of cannabis plants is often described as a high stress training method. Properly done, it will result in an even canopy and a greater harvest.
Improperly done, it can cause significant harm to leaves and buds. For this reason, it is important to do it at the right time during the vegetative state, which depending on light, water and soil conditions is usually between two and six weeks after germination.
Clean cuts are quicker to heal, so it would be wise to invest in a pair of very sharp, quality scissors. You can find a variety of specialty trimming scissors online made specifically for pruning cannabis plants.
- Disinfect the blades of your scissors with alcohol to prevent infection to your plants.
- A general guideline for the first cut is to remove the growth on the main stem above the fifth node. This allows for a reasonable number of branches below the cut to develop laterally. It will also result in two new branches to develop at that cutting point. Make that cut and you’ve doubled your yield.
- Future cuts to branches should be above the second or third node.
- Keep in mind that each cut is a wound, and like humans, plants need time to heal from them. Never top a struggling plant. Instead, monitor your plants allowing them two or three weeks to completely recover. When plants have healed, consider whether branches should be topped again and do so if necessary.
What is a Cannabis Manifold?
In the world of cannabis, the cola or branch that contains the flower clusters is the creme de la creme of the plant. This is the moneymaker, the portion from which the high concentration of cannabinoids and terpenes is derived.
Thus, any technique that can produce multiple, large, high quality colas on a single plant is worth its weight in gold.
A cannabis manifold is one such technique. It builds on topping by doing so three times at symmetrical nodes on the plant. This highly efficient practice results in a plant structure with eight main colas and multiple lateral branches.
It is particularly valuable for indoor plant training.
What Are Cannabis Mainlines?
Like manifolds, cannabis mainlines build on topping to also produce eight main colas and additional lateral branches.
However, rather than topping three times, mainlines are accomplished with two cuts preserving two branches from the first cut and four from each side in the second. The resultant plant is less symmetrical but no less valuable.
The Benefits of Mainlines and Manifolds
A plant with a single cola is not only less productive, it can also end up being completely useless if the bud ends up succumbing to rot. Manifolds and mainlines assist in the development of larger plants with strong, healthy canopies that produce a greater harvest and better buds.
Through manifolds and mainlines, the apical dominance is divided and diminished. These techniques are a simple way to keep from putting all your eggs in one basket.
Topping Technique to Maximize Harvests
Indoor growers have their own unique challenges in that they also want to produce higher yields but need to do so with far more limited space. Providing all plants with uniform access to grow lights will help to ensure they grow at the same speed and rate.
Two low stress training methods that have proven highly successful at accomplishing these objectives are Sea of Green (SOG) and Screen of Green (ScrOG). Both methods train plants into developing a horizontal canopy with multiple buds, and they each have their advantages and disadvantages.
A critical difference between these two methods is that SOG calls for bunching together a large number of plants in a small area. Because of this requirement, recreational growers limited by law on the number of plants they can raise may find ScrOG the better option.
With ScrOG, growers place a nylon or similar material screen between the light source and plants and as branches grow, stretch them out horizontally to expose a greater number of nodes to the direct light. Keep in mind that with the ScrOG method, some plants will still need to be topped or pruned.
At the end of the day, for maximizing a harvest, topping and pruning is the oldest trick in the book.
Advice on Topping Clones
The significant thing to remember about clones taken from a mother plant is that they need a little more TLC than seedlings. Their root systems are a bit more delicate, so give them ample time to develop before topping them to build a manifold.
When the plants are ready, choose a node with two healthy growth tips that are fairly close together and cut off all growth above. Be sure to leave the fan leaves below the node as the clone will need them for energy production.
Gently pinch or bend branches to force them into symmetry as this will inhibit dominant branches and allow for a more even distribution of energy to the colas.