I'm growing some plants from seeds indoors and they're coming up well. They sway toward the brightest light source, sometimes swaying so far they almost tip over. Some species do this more than others - e.g. 2" tall parsley is swaying much more than 2" tall chives. The brightest light, which they sway towards, is the window they're nearby when it's bright and sunny. They all enjoy a grow lamp directly above them, but they still seem to prefer the light. It could also be due to water mist being applied to them predominantly from one direction but we try to be gentle with misting and do it mostly from directly above them.
I have a habit of rotating their pot/planting trays so that they lean the other way. I see this as a kind of 'exercise' for them, and helping them form well-rounded growth. They do rotate and over the course of a few days will go back upright and then lean in the new direction of the window. Does anyone know, though, is it good to rotate young plants that are bending toward a light source?