Root lock out?

I noticed my one plant hasn't grown in a few days it seems or maybe I can't tell. Anyhow I know my ph is high like an 8 so that is more than likely my issue? I have them in 5 gal buckets so I know it shouldn't be out of room and its only 3 weeks old. I ordered a ph kit it just hasn't got here yet I just wanna make sure this could be the problem and what do I do? Thanks everyone.

...post pictures.

I took this earlier today if this isn't good enough I can take some more quick

it looks fine to me, and the pot is plenty big. but a ph of 8 is to high. just start watering wiht a ph around 6.5 no lower then 6 no higher then 7

Thanks for the info, maybe I got the newbie paranoia, my other 2 plants are still growing just fine. Hopefully my ph kit shows tomorrow.