A Beginner’s Guide to Topping Cannabis Plants and the Benefits Associated

There are many ways to increase yields when growing cannabis plants indoors, and one of my favourite methods is to use the topping technique. It is a simple but highly effective way to increase the number of crown shoots on a weed plant.

In this article, I will break down all you need to know about this easy-to-do technique, covering the right time to do it, the tools and equipment required, the benefits and common mistakes to avoid.

What Does Topping Cannabis Mean?

Cannabis plants are apically dominant plants, meaning they will grow with one central cola and lower side branches. This is because of the growth hormone named Auxin, which is responsible for a cannabis plant’s vertical growth. Topping disrupts this growth hormone, allowing the plants to focus their energy on the smaller axillary shoots.

The two axillary shoots then become the leading growth site. Instead of one central cola, the plant is capable of producing two. When a grower tops their plants multiple times, the outcome is a dense, compact and bushy plant capable of producing up to 12 main colas when flowering. Below is a list of how topping affects plant growth and the number of shoots it can produce over a long time.

• Topped one time = 2 crown shoots
• Topped two times = 4 crown shoots
• Topped three times = 6 crown shoots
• Topped four times = 8 crown shoots
• Topped five times = 10 crown shoots
• Topped six times = 12 crown shoots

When Is the Right Time to Top a Cannabis Plant?

This plant training technique works best, from my experience, when growing with cannabis seeds. The reason is that you can produce a symmetrical growth structure and start the topping technique once your plant has made its first internodal growth site.

Topping should only be done through the vegetative stage, so when the timer is set to 18/6. Growers who prefer a long vegetative stage have the opportunity to top their plants nonstop during this time, resulting in a plant that, when flowering, will produce an abundance of uniform colas.

Once a cannabis plant begins flowering, you should not top your plants any further, to avoid causing stress, and potentially slowing down growth during the transition stage (when plants stretch)

Tools and Equipment Needed for Topping

The best part about experimenting with topping cannabis plants is the fact that you do not need to spend a significant amount of money, and all you need are the following.

1. A sharp pair of scissors / or a scalpel
2. A healthy cannabis plant

The Benefits of Topping Cannabis

 

• Sativa-dominant plants can be shortened using the topping technique.
• Topping restricts the growth hormone Auxine, preventing tall plants.
• A grower can make one plant very bushy and the canopy dense.
• Topping is an easy-to-do training method perfect for beginner growers.
• Yields are significantly increased when topped during 18/6.
• All of the top canopy grows uniformly, and the buds are the same size.
• Topping can be combined with other training techniques.
• Applying topping before the flowering period reduces plant height.
• This is an excellent technique to use for outdoor cultivation.

Which Strains Work Best for the Topping Technique?

Below is an explanation of different cannabis genetics and how topping affects each one.

Indica cannabis plants

When topping indicas, you will end up growing a stocky and dense plant with short internodal spacing. It is recommended to defoliate and prune away fan leaves to allow more light to enter the canopy.

Sativa cannabis plants

Topping a sativa is an excellent way to keep them much shorter and allows them to grow with a wider growth structure. Sativas can benefit significantly from the topping technique, which prevents them from becoming tall, leggy, and oversized once flowering is induced.

Hybrid cannabis plants

Hybrids are a mix of indica and sativa genetics. When topping hybrids, you will not need to worry about them becoming overly bushy; however, pruning is advised to clear away the lower fan leaves for increased air flow and optimal light penetration.

Autoflowering cannabis plants

When growing autoflowers, be aware that you have only a 2-week period to train them before they start to flower, regardless of the light cycle. Topping autos can result in short-sized plants, and in my opinion, it is not worth it. Try using the LST method on autos from week 3 to 4 of growth.

3 Common Mistakes to Avoid When Topping Your Weed Plants

Using Blunt Scissors

You will want to make a clean cut when removing the top of the stem when topping a cannabis plant. Blunt scissors can harm the plant and may result in a poorly topped plant. To avoid using blunt scissors, simply buy a new pair from a local hardware store.

Topping Too Early in Veg

Applying the topping technique to young cannabis plants that are not strong enough to recover from the topping technique can set you back weeks, as the plant attempts to recover. Wait until the stem is around 1cm in diameter and the axillary shoots are well established.

Topping Autos More Than Once

If you are a beginner grower, be very careful when topping autos. One common mistake is overdoing it! 420 Seeds recommends that you only top once, and no more. Autos don’t have time to bounce back from multiple toppings, and it can severely stunt their growth and yield potential.

My Final Thoughts on Topping

Topping cannabis plants is easy to do, and as a grower, you can decide how often you want to apply the technique. Growers with limited height indoors who want to increase yields in small spaces will find that topping can help keep plants shorter as well as increase the number of colas. Try experimenting with topping your plants and see which strains work best for your requirements. Good luck!

Feature photo: These outdoor plants were topped early on, resulting in bushy plants.

Photos credit: Stoney Tark.