When left to grow in nature, most cannabis plants will take the shape of a long and thin Christmas tree with one main large flowering bud along the centre stem at the top of the plant. It is natural for the plant to reach as high as possible to compete with neighbouring plants for sunlight. The plant will prioritise growth to the parts of the plant that are in the most direct sunlight; this results in smaller less potent buds in the lower branches.
It is also natural for the cannabis plant to compete with itself. This means that the lower branches will compete with upper branches for sunlight as they reach for the highest or brightest spaces. This natural occurrence can be used to our advantage through various techniques, known as training.
In this article we will discuss the pros and cons of four types of plant training consisting of low stress training (LST), topping, fimming and SOG; including step-by-step instructions of how to make the most of each technique.
Low Stress Training: How to LST
Low stress training, commonly referred to as LST is exactly as it sounds. We exert low stress on the plant in order to train or manipulate the shape and size of the plant during the vegetative stage of growth.
- Prepare your pot by drilling a number of small holes around the circumference, close to the upper edge. These holes will be used to tie down your plants. Bamboo sticks can also be helpful for support.
- The plant is initially allowed to grow in its natural form until a good strong root system is formed. Gently bend the main stem of the plant and tie it down securely using string. Take care not to strangle the plant stem, allow some room for growth.
- The goal is to create and maintain a flat canopy whereby each branch is equal height, tying down when necessary as the plant grows. Readjustment of previous ties may also be required.
This technique is very beneficial for the home grower with limited space – the overall shape of the plant can vary greatly depending on the extent of training. The yield achieved through LST is far greater than without training and the quality of bud more uniform throughout the plant. You can achieve great results with LST particularly if you use tall strains such as Super Silver Haze, Amnesia Haze and G13 Haze, you can also get similar results but much faster using a sativa dominant auto such as Lemon Haze Auto. Autoflowers grow much faster and therefore don’t have much time to recover, so using techniques such as LST allows them to take advantage of maximised photosynthesis while inflicting less stress on the plant than other training methods such as fimming and topping.
Topping a plant
The term ‘Topping’ earned its name from the area of the plant which is affected. The top. As discussed previously, the cannabis plant naturally grows into the shape of a Christmas tree. Topping involves trimming the very top of the plant off.
With the top removed the plant now focuses its energy towards growth in the next highest branches creating a flatter, bushier plant. This shape promotes and encourages a level playing field for flowering sites to produce healthy buds.
- Prepare your pot by drilling four small holes (one on each side) close to the upper edge.
- When the plant has grown at least four symmetrical nodes, that’s branches growing off the main stem in opposite direction. Cut the tip of the plant off with sharp sterile scissors.
- Allow the plant to recover from the cut and watch how the two branches directly below the cut compete for the priority high spot. Once they have grown a few inches (approx. seven days) tie them down to create a flat canopy allowing the lower branches to join the competition.
Topping a plant increases yields substantially whilst minimising the stress experienced by your plant. The biggest buds are smaller than the larger central cola in untrained plants but the many moderate sized flowers more than make up for it. This is my favourite way to train cannabis plants because of the low maintenance and relatively high yields. Most strains respond well to topping, however it is the more Sativa dominant strains such as Nevilles Lemon Haze and G13 Haze that achieve the highest yields from this technique, due to the fact that it widens the plant and increases the bud sites more effectively.
Fimming a plant
Very similar to ‘Topping’ the Fimming technique uses the same principles in that the highest most energy focused part of the plant is trimmed to allow the lower branches to compete for the prime sunshine spot.
The difference is that when Fimming a plant, around 75% of the newest growth tip is cut away, which can prove to be quite tricky requiring a steady hand.
The result is that instead of two new branches competing at the top – four new branches form and create move flowering sites for bud to grow.
Sea of Green method / Screen of Green:
This final technique known as either sea of green or screen of green is the most superior of all the techniques discussed. We essentially create a flatbed canopy covering our entire usable growing area. The principle is the same, whereby we ensure each branch has the opportunity to compete for the prime sunlight spot.
Only this time we use a screen or a mesh to control the growth and push or tuck the highest shoots down beneath the screen. This is most easily done when growing in a small tent of around 1m x 1m or 1.2m x 1.2m.
You will need:
- Small to medium sized tent
- Mesh / screen (2 inch by 2inch squares)
- Available from most garden stores
- Method of fixing our screen in place (clamps/strong duct tape)
- Clamps are preferred is case readjustment is necessary
- Lots of care and attention
- Repot your plants into medium to large pots of approx. 18L capacity and space evenly into your 1.5m2 tent.
- Cut your screen to fit perfectly into the tent and attach it horizontally 15 inches above the top of the pots.
Follow the instructions above to ‘top’ each of your plants and allow them to recover for 7 days minimum.
- As your plants grow, allow them to extend 4-5 inches through the screen. Then bend each shoot down and tuck it beneath the screen spreading each plant to make use of the entire screen.
- Continue to tuck or tie down branches as they grow creating a blanket of cannabis plants.
- Note: trimming of the lower branches / leaves may be necessary for adequate air circulation.
When approximately 75% of the screen is occupied with potential flowering sites, it’s time to flip the light cycle to 12/12. Expect the plants to stretch and manage accordingly to maintain your SOG.
- Two weeks into the flowering stage, STOP training the plants and allow the buds to develop equally and uniformly.
- Every few days leaves and small branches containing airy small buds can be removed from BELOW the SCREEN.
When using the Sea of green (SOG) technique, yields are drastically increased, ‘popcorn’ buds are eliminated, the chance of bud rot or mould is reduced and the whole of your “garden” is subjected to the maximum amount if light possible. It does take a lot more care and attention to be successful but the rewards are most certainly worth the effort!