Yellowing of leaves

[Shovelhandle]

Hello everyone,
I am a first time grower and am growing some Sin City Diesel, 818 Deadhead OG and Julius Caesar. They're in the sixth week from seed. A couple of days ago I start noticing yellowing of my plants. I've researched it, but cnt find a picture that look like mine plants. Can someone please help me?Attachment 289412

looks like you may have got some nutrients on the leaves while feeding them?