How to train a cannabis plant
Growers use a range of techniques to manipulate growth patterns of cannabis and produce stronger, bushier plants with more terminal flower sites and larger overall yields. These techniques are relatively simple to master, and can be successfully used by novice growers—although they should not be overused. “Topping” simply refers to the act of cutting a growing shoot off the stem. By doing so, the plant is encouraged to direct extra energy to the next two shoots. Topping is performed on the main central stem at first, causing the two secondary stems to grow larger in compensation. Once those two stems have grown strong and healthy, they may be topped again to produce four main stems—and maybe again to produce eight main stems! As shown in the photo, a tiny section of stem should be left behind when topping, as if 100% of it is removed it may damage the next two shoots.
Growers use a range of techniques to manipulate growth patterns of cannabis and produce stronger, bushier plants with more terminal flower sites and larger overall yields. These techniques are relatively simple to master, and can be successfully used by novice growers—although they should not be overused.
Topping & “FIM”
“Topping” simply refers to the act of cutting a growing shoot off the stem. By doing so, the plant is encouraged to direct extra energy to the next two shoots. Topping is performed on the main central stem at first, causing the two secondary stems to grow larger in compensation. Once those two stems have grown strong and healthy, they may be topped again to produce four main stems—and maybe again to produce eight main stems! As shown in the photo, a tiny section of stem should be left behind when topping, as if 100% of it is removed it may damage the next two shoots.
“FIM”, otherwise known as “Fuck I missed”, was allegedly discovered by a gardener seeking to top his plants as normal, but missing slightly—leaving a slightly larger section of stem behind. If performed correctly, the two secondary shoots should grow as normal, with the addition of 2-4 extra shoots that grow directly from the stem remnant left behind.
Topping and FIM both allow the height of the plant to be controlled, and create bushier growth by encouraging more vigorous growth of lower stems to replace the missing central stem. It is advisable to top or FIM a maximum of three times when growing indoors, as the plant needs some time to recover from the stress.
Supercropping (or high-stress training)
Supercropping (also known as high-stress training or HST) is in essence a similar technique to those outlined above. The idea is to divert energy from the main central stem to the secondary stems, with the aim of increasing the number of main colas. However, instead of removing part of the central stem, the technique involves pinching the stem between the fingertips and bending until the inner part of the stem breaks—but if performed correctly, the outer stem and “bark” remains intact. The stem will then be unable to support itself and will flop loosely downwards.
While this still subjects the plant to considerable stress, it is not as severe as that caused by topping or FIM. Plants should recover quickly, and there is no loss of stem tissue and potential flower sites—but the plant is still “tricked” into thinking it has lost its main stem (as the nutrient transport tissues have been damaged), so it will pour its energy and growth hormones into maximizing lower branch growth.
As well as this, the main stem itself will recover and even grow stronger, as the site of the original break will form a swollen section around the damaged tissue in order to protect and repair the main stem. Ultimately, this collar of extra tissue will allow nutrients to be transported at a faster rate. Typically, this section will never regain its fully vertical position, but will remain horizontal. This will expose the length of the stem to the light, and encourage any small secondary branches between the break and the tip to grow vigorously upwards.
Low stress training
Low stress training (LST) refers to training techniques that are not invasive and do not lead to the stress levels seen with topping and supercropping. The main principle of low stress training is to maximize light exposure to as much of the plant as possible, and it is achieved by using wires, strings, yo-yos (in this case a kind of retractable elastic string on a roller), or some other device that will fix stems in position without causing them damage.
The LST technique typically involves forcing the main stem to grow in a horizontal direction rather than vertical. The main stem is pulled downwards and fixed into position, and trained to continue growing close to the ground. As a result, the lower branches are suddenly exposed to dramatically increased light, and they are encouraged to grow vigorously towards the light. With time, there should be several strong stems growing up towards the light. The original main stem will also attempt to resume vertical growth; this can be prevented entirely, or it can be permitted once it is deemed that the lower branches have developed sufficiently.
Some growers use LST in combination with topping or FIM—at first the plant is topped to produce more “main” stems from the lower branches, and once this stage is complete the main branches are pulled outwards and downwards and fixed into position. This increases the “spread” of the plant considerably, but allows even more of the lower branches to access the light, and grow strong in response to the increase in light intensity.
Removing lower branches (and “lollipopping”)
While the above techniques are typically performed during the vegetative period, the final type of training that we will discuss in this article is often performed in the mid-to-late stages of the flowering period. The technique involves removing the majority of the leaves and stems from the bottom 1/3 of the plant—as the distance from the light source increases, the light intensity available decreases proportionally.?Thus, below a certain point the plant is putting energy into growing flowers and leaves that will remain negligible in size due to the lack of light intensity.
Removing the lower branches and leaves at a point approximately mid-way through the flowering period will encourage the plant to channel its energy into the upper flower sites, thereby increasing their size and weight. If the lower branches are removed too early, the plant may just put out more stems and leaves; if they removed too late, more energy will be wasted on negligible flower sites, and when this energy is finally diverted to the upper buds there will be insufficient time for it to noticeably affect yield.
This technique can be taken to extremes and used to produce plants with just one central cola and no lateral branching at all—some growers find this desirable at it leads to the formation of huge, chunky central colas. This extreme form of the technique is known as “lollipopping”, and it is usually performed at just two weeks into flower—so a little earlier than the standard technique for lower branch removal.
However, most growers will use a variety of other training techniques before removing the lower branches. If performed correctly, this will produce an even canopy of multiple tops which will produce plenty of evenly-sized buds, and a lower third devoid of small, useless branches and leaves.