Discoloration only on a few top leaves - Any ideas? Anyone?

These photos are from a SCROG grow so I cannot tell if it is on just one plant. All lower leaves are good. Only 2 or 3 stalks show this discoloration and their leaves are a lighter green. They are also all close to the center, directly under the light.

Any ideas? My best guess would be light burn or an iron def according to what I have read. If it is an iron def what should I do? Throw a few nuts and bolts into the res? I already changed out the res but do not have an iron supplement.

Just a few are like this


The rest look healthy like this

MuckyDucky said:

These photos are from a SCROG grow so I cannot tell if it is on just one plant. All lower leaves are good. Only 2 or 3 stalks show this discoloration and their leaves are a lighter green. They are also all close to the center, directly under the light.

Any ideas? My best guess would be light burn or an iron def according to what I have read. If it is an iron def what should I do? Throw a few nuts and bolts into the res? I already changed out the res but do not have an iron supplement.

Just a few are like this
View attachment 2975993 View attachment 2975992

The rest look healthy like this
View attachment 2975994 View attachment 2975995

Click to expand...

pretty much answered your own question