Stelo della pianta

I feel both @Vexar and @Superglue are correct, Vexar provided you with the why, as seedlings tend to stretch more when looking for a light. @Superglue suggested "Wind Shake" to make the stems stronger, but first take Vexar advice and add support to stabilize your plants, I use a very fine wire almost 100% of the time on my plants, if you feel it is to much stretch, then increase the intensity of your light, or move it or your plants closer to one another, just make sure that the light does not burn the plants, you can stick your hand between the plants and the light to measure the radiant heat from the light, Happy Growing Brother!