There are several causes for a pot plant to become spindly and stretch. Often the pot plant appears it's reaching for the light. pot plant stretch can occur in both the vegetative and pot flowering phase.
Many pot growers will allow their cannabis plants to stretch.
Stretch is generally considered an unavoidable evil, but some pot growers prefer a bit of stretch to allow for premium pot buds.
Encouraging pot plant stretch can be a good technique to prevent budrot in susceptible cannnabis strains while producing massive pot colas.
Is pot plant stretch a problem?
Cannabis plant stretch is a problem primarily in indoor pot grows because it may reduce yields in some pot strains.
Stretch produces tall lanky pot plants with possibly weak and spindly stems.
The weight of pot buds during pot flower will require staking or roping to avoid damage, falling over or even snapping off.
Pot plant stretch may be a sudden problem for weed growers with limited ceiling height in their grow tent.
Stretched cannabis plants are tall and their lower pot bud sites receive exponentially lower lumens than top cannabis colas.
Tall pot plants require more water and pot fertilizer.
Stretched pot plants may yield 30-50% less.
How can I minimize stretch?
Purchase pot seeds that produce compact cannabis plants.
Numerous pot seeds are geared to remain short squat pot plants.
Indicas tend to have minimal pot plant stretch compared to Sativas.
Keep lights at the optimum distance.
If you notice your pot plants (especially seedlings) growing quickly like they're reaching for the lights then it's time to move the light lower. Improperly distanced lights is the major cause of pot plant stretch.
Use blue-spectrum light. Many pot growers opt for Metal Halide light exclusively during vegetative phase to help keep pot plant internodal length shorter.
Use adequate spacing.
Don't let your pot plants crowd each other. A crowded pot grow room will have weed plants fight each other for light by growing quickly or stretching on top of each other. Too many pot plants is not good.
Minimize cannabis plant stress
Stretching can be reaction to a variety of environmental stresses (light, high humidity, low/high temperatures, transplant shock, leaf loss, etc). Maintaining optimum growing conditions is your best defense against stretch.
How to fix pot plant stretch.
There are numerous methods of solving stretch.
Pruning, FIM'ing and topping
Pruning pot plants in veg and early cannabis flower flower will keep the plant from growing skyward. However, it may become a bushy plant. Some pot plants (like Sativa) do extremely well when they are pruned in their third to fifth week of vegetative pot growth. Other cannabis plants do not like to be pruned at all. Of course these pot strains won't be stretching. Note: Pruning in SOG systems is not recommended, as this promotes bushiness.
Turn Speed On Oscillating Fans Up
A surefire method of strenthening pot plants is to have them blowing in the wind. So to speak. A good breeze not only is great for airflow but also to give the pot plant an opportunity to toughen itself. Outdoors pot plants are subject to all kinds of weather. Indoors they recieve very little weather extremes. Diverting energy to strengthen itself the pot plant will stretch much less.