Growth node seedling ?

it informs about light intensity ... if you get too much stretch between nodes, probably need a bit more light. If it's too tight, need to reduce light a bit. There is such a thing as too tight. If leaves are pushing on each other from point they originate off stem or the branches are so close that everything gets congested etc etc... too tight can sometimes be worse than too lanky. Too much light will stunt a plant eventually and it doesn't just snap out of it immediately upon fixing the problem. new grwoth will tell about recent choices of light intensity. This relies on familiarity... you'll know what is a healthy node spacing quickly.

Node spacing is just the distance between nodes (where each new set of leaves/branches comes out of the main stem). After the cotyledons (seed leaves), the first set of true leaves is your first node, and you count from there. Tight/short spacing usually means your light is close/strong enough and the plant stays nice and compact. Long spacing (stretching) means the light is too far or weak and the seedling is reaching for it. So yes, you can use node spacing to judge light distance: if it’s stacking too tightly, raise the light a bit; if it’s stretching, lower it (without getting too close to cause burn). There’s no “perfect” spacing because each strain is different – just aim for healthy, steady growth with green leaves and not too much stretch.