HST And LST Techniques For Training Your Cannabis Plants
4 min

HST And LST Techniques For Training Your Cannabis Plants

4 min

Training cannabis can improve overall performance and yields. High-stress training and low-stress training are two styles of manipulating marijuana for better results indoors and outdoors. Find out more about the different techniques below.

Applying training techniques to the cannabis plant can improve end yields considerably. From knee-high, meticulously tied down autoflowering varieties to 3-metre-tall outdoor trees controlled with large trellises, training cannabis works.

What is the best way to go about training cannabis for improved performance? Well, first a shout out to the cannabis plant itself. Virulence is a feature of cannabis that is never strain-dependent. Revisiting a big outdoor plant that was previously ravaged by grasshoppers, only to find it now smothered in healthy regrowth, testifies to the hardy nature of cannabis.


Training Your Cannabis Plants: LST VS. HST

Despite its natural vigour, a bit of loving torture can get a very positive response from cannabis in a number of ways. At its simplest, low-stress training or LST exposes as much of the leaf surfaces to light during vegetation as practical; then, during flowering, as much bud surface as possible. Indoors or outdoors, where direct light strikes, optimal plant growth occurs. As suggested by its name, LST techniques are less harsh on plants, usually only slightly lengthening total grow time.

High-stress training or HST methods can seem traumatic and counterproductive, but administering controlled stress to plants can stimulate very strong growth in response. In a purely practical sense, training can also save space; many strains can get out of control quickly if not managed. HST can extend the grow period significantly depending on which methods are used, and how often. After all, the plant requires time to redistribute growth hormone to relevant parts of the plant.

There is no singular preferred training method when it comes to marijuana. It isn’t so much that one method is better than another, only which proven method, whichever it may be, suits your particular situation. Weed loves the sometimes counterintuitive attention, rewarding the grower with lots of that dankness we all enjoy so much.




For the grower who doesn’t have too much time, or the beginner who wants to understand the basic nature of the cannabis plant, bending a young plant to lay horizontally to continue growth is LST at its most basic. All the side branches will grow to a similar height, and the main cola will bend around to join the new canopy.

Taking things a step further, all new growth can then be tied down as close to flat as possible. This interrupts the apically dominant nature of cannabis, promoting equal growth at all nodes. Similarly, during flowering, buds will be homogeneous in size, rather than featuring a dominant cola with smaller satellite flowers. Plants end up being flat and broad, and take up little volume while making the most of the light footprint.


Outdoor growers know that mild damage caused to cannabis plants during storms can bring on a spectacular recuperation. Twisted branches and bent colas right themselves and visibly strive towards the sun.

Supercropping indoor crops mimics this kind of gentle damage. Physically bending the ends of upper branches to 90° has two effects. The lower buds can grow larger in more light, increasing overall bud volume. Plus, the bent buds respond with more vigour as the plant rushes to repair the damage.

Holding the chosen branch between thumb and forefinger, apply slight pressure and roll the branch backwards and forwards. When the stalk softens, gently bend it horizontally. No snapping, just a firm encouragement. An impressive knuckle of scar tissue will form in a few days.


Screen of green or ScrOG is low-stress training taken to the max. Early topping and training produces very bushy plants. A metal or plastic screen is fitted at canopy level and all new growth is tucked under the screen. Vegetation time is extended and plants are topped and trained to form a flat sheet of cannabis. All growth below the canopy is removed to create a manifold that promotes air circulation below, and every square centimetre of available light area is used. The flat canopy makes the most efficient use of available light, and buds are uniform and grow from every node.


HST: High Stress Training Techniques


Both topping and fimming remove plant material in order to produce a bushier plant with more flower sites, closer to the light source.

Topping involves fully removing new growth at the crown, and later on the side branches. The two branches below the cut will grow longer to form main flowers, and lower branches can catch up to be closer to the canopy. Topping side branches does the same thing to create a bush rather than the traditional Christmas tree silhouette.

Related article

How To Top Your Cannabis Plants

Where topping removes all the new growth at the tip, fimming (Fuck, I Missed) cuts the new growth tips in half. This slows new growth as there is less leaf matter to absorb light, which allows branches below to grow longer and closer to the canopy.


If you just want to grow big buds only with no secondary or popcorn buds, mainlining may be for you. Plants are topped a number of times to create a number of main branches. Topping three times will produce 8 main branches (4 times = 16, 5 times = 32), which are tied down and kept well spaced. Any new growth below the primary bud sites is removed (called undershucking), so the plant concentrates all its energy into producing large colas only.

When performed outdoors, mainlining ends up producing plants with extensive canopies, with all leaf and flower growth removed inside the plant. Plants only produce large, well-spaced colas in the canopy and no secondary growth, which makes harvest and trimming a comparative breeze.

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Main-lining Cannabis: Everything You Need To Know


Certainly the most controversial high-stress training method that varies in intensity from grower to grower. Defoliation involves removing leaves at least once during veg, and then once or a number of times during early flowering. Large fan leaves are removed during vegetation to encourage stronger growth throughout the plant. Then, more large leaves are removed just before the 12-12 flowering light switch, then again in the early weeks of flowering. During the explosive flowering stretch, the plant responds by producing more calyxes to make up for loss of photosynthesis ability.

Indoors and outdoors, training the cannabis plant gets very satisfactory results. Bud quality is improved, with fewer-to-no substandard nuggets. Grow spaces are made more efficient by producing more bud per watt of better weed. It is doubtful any high-quality contemporary cannabis is left to grow naturally, instead being subjected to one or a combination of training techniques to improve plant performance and increase yields. High or low-stress training brings out the best in cannabis plants.

Miguel Antonio Ordoñez
Miguel Antonio Ordoñez
With an AB Mass Media and Communications degree, Miguel Ordoñez is a veteran writer of 13 years and counting and has been covering cannabis-related content since 2017. Continuous, meticulous research along with personal experience has helped him build a deep well of knowledge on the subject.
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