Advice for a newbe

Hi all This is my first attempt and they look really good but I have just noticed that one of the steams is very thin at the point it comes out of the rock wool only half as thick as further up the steam I also noticed that the top of the rock wool is quite green. I am using a Hydroponics setup flood and drain watering on for 5 min twice in 24 hours, all of the plants have new growth and are around 6”to 8” high. I have added a pic. Any help would be great.
Thanks Barry

I know nothing about hydro growing being a soil guy. But that looks like some kinda critter damage.

^^this. Soil grower as well, but it kinda looks like these guys.

http://mtwow.org/Ceutorhynchus-litura.htm

Yup, something's eating away at that stem. Is it the rockwool that has something going on the surface?

timbeeeeeer

ive grown hydro before.....u may be watering too much early on, 5 min twice a day isnt much but those rockwool cubes hold water for a few days when the plants are young.......seems like your stem is rotting and algae is growing on your cube.....water only when the cubes require it early on

it might be tht when ur over watering it makes more humidity which can create mold or spidermites or any kind of bug because they like that shit and it also looks like ur over watering because that little glimpse of the leaf and has kind of that bleach white looking this usually means your overwatering

and do you have rats or any small pets at your house
lol cuz its like a small beaver tried making a goddamn beaver damn.....oh my god you found dwarf beavers! your a genius!!!! lol

I believe you have stem rot. I know there are products that can help, but I dont know them... Perhaps putting a 1/2 teaspoon of hydrogen peroxide in your watering schedule might help to kill of the negative shit, as well as aerate the substrate. I use h2o2 every watering, so its not gonna hurt it, just dont know if it will kill off the rot.

Can anyone second this motion?

If your Rockwool is staying too wet and I am assuming the top of the rockwool can be seen (is exposed) you probably have algae growing on it. You can water less frequently but also you can use something cheap like aluminum foil to make a shield between the rockwool and your light, this will kill the algae or at least should, future grows use this before the algae shows for best results.

well hydrogyn peroxide only work in light so if you wanna totally neutralize it you have to make sure all your lights on but it creates foam like substances too and i dont think thats good for it but im not sure its worth a shot