Low Stress Training (LST) is a gentle plant modification technique to maximize light exposure and improve the overall structure of the plant canopy. This method involves subtly bending and securing the main stem and branches to encourage horizontal growth instead of the plant’s natural vertical tendency. The goal is to create a flat, wide canopy where all growing tips receive uniform light, which significantly increases potential flower sites. Achieving this outcome depends heavily on initiating the process at the correct moment in the plant’s life cycle.
Identifying the Optimal Time Based on Plant Development
The most effective period to begin LST is during the plant’s early vegetative phase. Specifically, you should wait until the plant has developed between three and five distinct nodes, which are the points on the stem where true leaves and side branches emerge. Waiting for this specific growth stage ensures the plant has established a robust root system and enough stored energy to quickly recover from the minor stress.
This timing is critical because the plant’s stems are still young, soft, and highly pliable, making them easy to bend without causing irreversible damage or breakage. Bending the main stem disrupts the flow of the growth hormone auxin, which normally concentrates at the apex, promoting vertical growth. By redirecting the main stem horizontally, the plant distributes this hormone more evenly, encouraging the lower side branches to grow upward and become dominant flower sites.
Starting the training too early, when the plant has only one or two nodes, risks stunting its growth because the root system is not yet strong enough to support the intervention. Conversely, delaying LST until later in the vegetative stage means the stems will have developed thicker, more rigid structures. Attempting to bend a mature, inflexible stem dramatically increases the risk of snapping it, which can cause significant damage and require a lengthy recovery period.
Executing the Initial Training
Once the plant has reached the ideal three to five node structure, the first training intervention can be performed. Before beginning, gather soft plant ties, such as Velcro straps or rubber-coated garden wire, which will secure the stem without cutting into the tissue as it grows thicker. Rigid materials like thin string or uncoated wire should be avoided.
The first physical step is to anchor the base of the main stalk to prevent the entire plant from being uprooted when tension is applied to the top. This anchor should pull in the opposite direction of the intended bend.
Next, gently take hold of the main stem near the top node, which is the softest and most flexible part of the plant. Slowly and carefully bend the main stem over until it is nearly parallel to the soil surface; the ideal angle is a gentle curve that results in a roughly 90-degree bend relative to the ground.
Secure the bent stem with a soft tie, fastening it to an anchor point on the rim of the container or a stake in the soil. The tie should be snug enough to hold the branch in place but loose enough to prevent constriction as the stem expands in girth. This initial action immediately exposes the previously shaded lower growth sites to direct light, triggering their rapid upward growth.
Maintaining the Low Stress Structure
LST is a continuous process requiring consistent monitoring and adjustment throughout the vegetative phase. The plant will naturally try to correct its orientation, so the main growing tip will begin to curve back toward the light source within hours of the initial bend. This phototropic response is expected and is the reason for the ongoing maintenance.
You will need to check the plant every few days to a week, or more frequently depending on its growth speed, to adjust the existing ties and secure any new growth. The goal is to continuously bend and spread all newly growing branches outward and downward, ensuring every shoot remains at a similar height to maintain a flat, even canopy. This consistent training ensures that the plant’s energy and resources are distributed evenly among all growing tips, maximizing the number of potential flower sites.
During this maintenance phase, LST can be easily combined with other techniques, such as minor pruning or defoliation, to further improve light penetration and airflow through the dense canopy. The focus remains on gently guiding the plant’s structure; any new growth tips that rise above the canopy should be gently bent and tied down to maintain the uniform, horizontal structure. Active training should continue until the plant enters the early flowering stage, at which point the structure is largely set, and the focus shifts entirely to flower development.