I realized I had my grow light too high and the sprouts stretched too tall and fell over. I have two fans blowing on them, one is oscillating, the other is stationary and only comes on for 18 hours with the light. Out of 9 sprouts I had to tie 3 of them up with string to hold them upright. Another is growing at kind of an angle and I worry it will fall too. On the ones I have hanging with string the bottom of the stem near the soil has thinned out to the point where it is almost non-existant after a few hours. What is causing this? Other than the fact they are stretched the sprouts seem healthy with nice green leaves.