Why Could this one be yellow?

This plant is growing "ok" but I'm wondering why the little round leaf
is turning yellow..

I've got a few ideas of my own but I just want to get some other opinions on it.

It's 10 days old watered every 5 days, for the last few times, watered with a little 7-7-7 added in the water because the plants had fallen over but now they are doing ok, theres three plants altogether but only one of them is doing this(the little yellow round leaf), they are all being treated equaly and the pH is around 6.5. It's on 17-7, all the lights are CFL's, there are 9 CFL's on the 3 plants with about 8800 lumens altogether.

Any one got any ideas.

You shouldn't be fertilizing yet at ALL.
I assume that is shultz fert. You'll want to look into cannabis-specific fertilizers when the time comes to use them (after 5 nodes have formed).
The yellow leaf tips are fert burn. Water heavily with plain tap water until some water runs out the bottom of the pot.
The round leaves turn yellow as the plant no longer needs them anyway, so don't worry about those.
Go sox.

Thanks so much, I was curious because this is the first grow so i wast to shure about what was gonna happen to the little round ones. The only thing i knew was that they could be roots if i planted them diffrently.

The round leaves can never be roots but that part of the STEM below them can GROW roots very easily.

OOOHHH, Well, any who, thanks for all the info. I think i might start a grow log but im not to shure yet.

Quick question though, How do I get a Signature? I don't see it under the CP.

You have to have more posts. Then it's under 'options' I think.