yeah heard this too about folks sticking nails thru parts of the stem..
there is a reaction in flow of some chemicals or enzymes in their vasular system (Xylem and phloem)
from what I read awhile ago once you super crop them (or add a nail or stress them) this is the reaction that happens. less phloem or less xylem is produce into the effected area of the plant causing the plant to feel that something is wrong and making it fruit or flower.. and well it suppose to work have never tried the nail or stressing them on purpose but.. I am thinking the science is there
The xylem and the phloem are essential parts of the plant which carries nutrients from the roots and by products of photosynthesis from the leaves to all the parts of the plants. By breaking these important parts of the plant, the plant automatically tries to heal this injury.
Through crimping, the cannabis plant concentrates on healing this injury and places all nutrients on the crimped section rather than allocate it for further growth. Thus, this technique is advisable if your cannabis plant is a fast grower. Not only that, the plant will rebuild its broken parts sturdier and improved than before, thus making the whole plant stronger. On perfect growing conditions, the repair of the broken xylem and phloem would only take twenty four hours.
In simple terms, crimping is squishing some portions of the plant using your finger, particularly your index and middle finger, but being careful not to completely flatten the stem. The ideal location to crimp a plant is in a section of a stem below a node. You can crimp your plant as early as its seedling phase.
Use both of your hands, so that accidental pulling of the root could be avoided. Having the other hand as a support, gently twist the part to be treated with two fingers until you hear a soft snap. For more mature branches, you could have two hands twisting on opposite directions. For younger stems, twisting is not necessary. Only a firm grasp will cause the breakage of the inner layer.