High temperatures, high transpiration, high turgor pressure, and lots of cell elongation. Cannabis plants can sense and respond to their surroundings. They don't have brains like humans, but they have evolved sophisticated ways to perceive and react to various environmental cues, including light, gravity, touch, water, sound, and even the presence of other plants. This ability, known as plant perception, allows them to adjust their growth, defend themselves, and even communicate with each other. Infrared light, particularly near-infrared (NIR), can influence plant growth and development by impacting various processes including initiation and elongation. UVB radiation inhibits stem and hypocotyl elongation in plants. Moderate UV-B exposure can cause a decrease in stem and leaf elongation, leading to a more compact plant architecture. Higher UV-B intensities, like 7.5 kJ·m−2, can lead to reduced elongation. So it becomes a dance of initiating a stretch to seek to higher ppfd, then whenever you want the stretching to slow down,UVB inhibits the stretch by altering hormone balance,, coupled with the high-intensity dli once you get her to a height where you want. Being autos I don't have much time to play around. So we are playing fast and loose, get stretched, and then spread her open. You get the idea. 86F 30% RH with the lower side of optimal on ppfd, with a smudgering of infra-red to initiate response of making her stretch more so than normal. Once she sprouts up in height, I drop metrics to 77F 55%RH% while upping the ppfd, giving her a dash of extra 430nm, giving the grow more of a 6000K. This encourages denser growth with less elongation. Higher side of optimal PPFD, with the auxin hormone balance changed, the side stems are starting to shoot up to the same canopy level as the apex (almost). Normally takes me 2 untrained toppings before a plant will flatten its canopy. I didn't take enough off the apex to do it in one chop, it was only day 10, so there really wasn't much to top from without creating unpredictable results using fim, opted just to keep it to a clean topping. Even predictability over the Chaos of the"Fim". Brainfart: Remember, the veg stage creates the skeleton that will stretch out into flowers. How dense you create the skeleton through light intensity will determine the density of your clusters as they form cola, as long as you can keep up with the demands. Increasing light intensity generally leads to plants having shorter internodal spacing, meaning the distance between nodes (where leaves grow) on a stem is reduced. This effect is particularly noticeable under LED grow lights, with great stress comes great dense clusters. Hello, temperature, my old friend! Goodbye, money on AC. What did the flower decide to study in college? STEM.