Thinner stems on bottom. Normal?

First timer. Critical auto flowers at 3 weeks. I think I’m losing one but 4 look pretty good. Are they getting too tall and not full enough? Their stems are thinner on the bottom than the new growth? Is this normal? I raised the lights today to about 18 inches. They’re getting new growth. Just worried they aren’t getting full enough. Maybe I’m expecting too much for just 3 weeks? Any and all help appreciated. Thanks

Some pics



Patience young Jedi. Channel your energy and they will grow as destined. Your girls look pretty good, just a little slow out the gate. Not to worry they are growing underground too and that is not apparent to us mortals. The growth may shock you when they get a good footing.

:rofl::joy: okay okay. I’m trying to stop the worry. Loving this so much. Just trying to do my best for them. Thank you, Master Yoda. Oooohhhmmmmmm

Pretty normal. You can add more soil and that part of the stem will sprout roots

Thank you!