Low-Stress Training (LST) is a plant training technique for cannabis that aims to enhance the yield and optimize the growth pattern by manipulating the plant’s physical shape. LST involves bending and gently manipulating the plant’s stems and branches to change its natural growth pattern without inflicting significant damage. This is in contrast to High-Stress Training methods (HST), which involve more aggressive techniques such as topping or fimming. The underlying theory of LST is to make the most efficient use of available light, subsequently boosting the plant’s photosynthesis process and promoting higher yields.
Principles of Low-Stress Training
Low-Stress Training techniques are based on the principles of plant phototropism and apical dominance. Phototropism refers to a plant’s instinctual tendency to grow towards a light source. In its natural environment, the cannabis plant tends to grow vertically with one main cola (the central stem), which receives the most light and develops the largest and most potent buds.
Apical dominance refers to the phenomenon where the main cola inhibits the growth of the lower branches, ensuring that the plant’s energy is primarily concentrated on the topmost bud. This is an evolutionary survival mechanism in plants to optimize light absorption in a densely vegetated environment.
In indoor growing scenarios, this natural growth pattern may not be optimal as it may lead to an uneven canopy and inefficient use of artificial light sources. LST aims to tackle this issue by breaking the plant’s apical dominance, encouraging the growth of multiple colas, and creating an even canopy that maximizes light exposure to all parts of the plant.
Low-Stress Training Technique
The process of LST begins when the cannabis plant has at least 4-6 nodes, typically a few weeks into the vegetative stage. The plant should be healthy and vigorous, as any stressors like pests or nutrient deficiencies can impede the LST process.
Bending the Stems
Using soft plant ties or garden wire, the main stem is gently bent over and secured to the side of the pot or grow container. The aim is not to completely flatten the plant but to create a bend that encourages lateral growth. The bending process should be gradual and gentle to avoid snapping the stem. The ties should not be overly tight and should be checked regularly to avoid cutting into the growing stems.
Encouraging Lateral Growth
Once the main stem is bent, the plant will start to redirect its growth hormones, known as auxins, towards the lower branches, thus breaking the apical dominance. The lower branches will start growing upwards towards the light source, forming additional colas. As the plant grows, these new colas may also be bent and secured to encourage an even, bushy growth pattern.
Maintenance and Adjustments
Throughout the plant’s growth cycle, the grower should regularly monitor and adjust the ties as necessary, ensuring all branches receive equal light exposure. It’s important to note that LST is a continual process that may need to be adjusted as the plant matures.
Benefits and Drawbacks of Low-Stress Training
The primary benefit of LST is the increase in yield due to the enhanced light absorption by all parts of the plant. By training the plant to grow in a more lateral or bushy pattern, more bud sites are exposed to the light source, resulting in the development of multiple colas. This can significantly increase the overall yield compared to untrained plants. Moreover, LST is a non-invasive and reversible technique, allowing growers to rectify any mistakes and adjust the plant structure throughout the growth cycle.
Despite its benefits, LST requires a significant time commitment and attention to detail from the grower. It also increases the complexity of the growing process, potentially making it more difficult for novice growers. Furthermore, while LST is generally considered low-stress, if not done correctly, it can cause damage to the plant, resulting in stress and potential yield loss.
Mastering Low-Stress Training can significantly optimize cannabis cultivation by increasing yield and ensuring efficient use of light. While it requires careful execution and ongoing attention, the potential benefits make it a highly valuable technique for cannabis growers aiming to maximize their crop’s output. As with all cultivation techniques, patience, experience, and continual learning are key to success.