Why is my plant yellowing?

[Carly95]

They are under a 400watt hsp they have been overwatered would that cause the yellowing they in canna terr pro plus mediam

 

[smokeweedman]

Turn off HPS and then take photo. its nature and nature isnt perfect so calm down.

 

[arteekay]

Although a little blunt, smokeweedman is correct. We need to see under normal white light to get a good idea.

Overwatering can cause all sorts of problems. Most important is to ascertain if the issue is progressing or not.