Swapped my grow lights for a south window, tomato stems doubled in 2 weeks
I was dead set on buying a second LED panel for my balcony setup, spent like $80 on the first one and thought more light = better. But my neighbor across the hall has this crazy tomato jungle and she told me she never uses grow lights, just puts everything on the south side where the sun hits from noon to 6pm. I moved my cherry tomato seedlings next to her spot and within 14 days the stems went from skinny and pale to thick and dark green. The LED panel still works for my herbs in the shady corner, but for the sun lovers I'm a convert now. Anyone else found that natural light beats the fancy stuff for certain plants?
How old are those seedlings though? My buddy did the same thing last spring and swore the window was magic. Turned out his plants were just hitting that stage where they thicken up on their own anyway. He moved them back under his cheap shop light a few weeks later and they kept right on growing. So it could be the sun, or it could just be timing, and you won't know unless you run both side by side.