Last couple weeks and fading fast - HELP?!

Ok, so I have two Juicyfruit x Northern Lights #5 x Skunk plants. Both have been perfectly fine up until the last two days or so.

First, what used to be my mother plant. It's a good size and has been flowering for the past month+ with no issues until just yesterday. Over night my leaves went completely yellow on me and the ones towards the top buds are crispy. This is my first grow, so I'm new to every aspect of troubleshooting. Any insight is appreciated.



Then there is a clone of the mother. It rooted in about a month in soil and has since progressed to about the same visible level of quality, if not a little better in less than half the time. I dig it.

Since last night though, the leaves have gone from a near-perfect green colour to a sickly yellow-green with spots of brown and yellow on them.



Nothing has changed nute-wise. It's actually the same 10L jug I mixed earlier even. Any ideas as to what has caused this?

It doesn't show in the pictures (crappy cell cam) but the buds are actually looking really nice on the clone, so I'd hate to lose it.

Thanks!

perhaps...change your nutes?

Well yea, that's done now. First thing I did. I should add, on that topic, that they're only 3 days old. Not like weeks old or anything haha.

Anything else?

So what's the deal here? Some folks get responses while others get nothing.

I realize it's a pretty amateur question, but clearly I don't know what's up so am now asking others.

Any insight's appreciated...

What kind of system? See if your leaves look like any on http://www.marijuana-seeds.net/Thanks-ThankYou.htm

600w HPS in a 2x2x5 tent. Air cooled reflector with a 465cfm fan. The spots spread throughout a plant in a day or so, starting in the middle (?) and as things stand now the plant has more brown than any other colour on it. I've cut down a fair bit of it in the last 3 days, figuring it was better to harvest early than to harvest crispy-dry colas and what not.

Do you give your plant just water once and awhile...looks like salt build up locking out some nutes.
Soil right? What is your Ph?
NPK of nutes? eg.(20-20-20)

Yup, soil. I'm running the GH Flora line and just got myself some molasses for the following grow. Kind of a lost cause to use it on this one I think.

I just recently started watering with just water every now and then. Every third watering for the last 3 weeks has been plain water. NPK-wise I just made the switch to the Lucas formula in hopes of keeping things a little simpler. I don't know the NPK off hand, sorry.

I don't think it's an overnuting issue, but like you said, a build up problem...which then becomes an overnuting problem. Within three days my whole crop (6 girls) showed those brown patches/spots and declined crazy-fast. I have two still standing and they're looking pretty good, but that doesn't mean anything apparently eh? Haha.

Any suggestions Lime?