Please Help save my Girls.

I think they might be in some real danger, i dont know what has happened but for the last week all new growth has been growing in puny, and tooth pick sizes. All scrunched up and conical,no longer flat long wide leaves. Not just at the top but all the in between node branches, and not just on my most mature plants but even the prout that was healthy and huge for its first couple sets. So this obviously points to an environmental stressor, no?
Or could they all need more oom and perhaps be getting root bound? Before there would be growth going from sprouting to 2 inches long and 1/3 as wide in a week has grinded to all new growth taking a week to develop into the tiny little crumpled toothpicks you see below. Anybody got a read on whats happening?
PLants are 7-8 inches tall in 6 in diameter pots. Light is hps 150w 7 in away from plant tops, temp between 77-87 and hum. 38%-62% (working on that).

Are you talking about the growth in the very center of your plant? The new growth, cause if so, the leaves start out small like that and have a tendency to grow smaller fan leaves around the nodes as well. As for the size of your plant and the size of your pot, I would say that it would in fact be root bound. Get a bigger pot, but be careful transferring it. Also, are your temps up and down those 10 degrees all the time? If so, you should get that dialed in to be at one temp when the lights are on and one temp when the lights are off. It also appears like your leaves are drooping which is a sign of over watering. Before you water, stick your finger in the soil about a half inch and see if it is still moist, if it is, don't water it yet. That's about all I got atm.

Over watering like the previous post said, as well as, the technique to check when to water.

Another simple technique too is lift the pot when you've watered and when it needs to be watered, giving you a fair evaluation of your watering schedule.

Not sure about the droopin, they perked right up this morning so ill watch the watering. Im going to transfer them to a larger pot today, what should my mix for the soil be? 20% perlite i heard is a good mix. I'm just more concerned about this tiny, wavy, crumpled little yellowing new growth that is happening all over the plant. Like i said before, in a week these would go from node to 2 inch long prong leaves wide as a finger. Now a week gets me those little..... Toothpicks.
Its as though something is preventing them from growing wide and straight long leaves, and nothing has changed in the grow area.
Could constant high humidity (60%) cause this to occur? Or perhaps a combination of root lock, high humidity and regular 10 degree temp swings between 75 and 85?
Everything was dark green and big, long healthy leaves on all plants until recently.

High humidity is favorable in veg and early flower, the temperature as well 85 below works fine too. It's not the "best ideal" but MJ can certaintly grow well.

Dark green leaves are a sign of nute burn. I'm thinking you MIGHT be overdoing the nutes and recommend just flush it with R/O-Distilled Water. And, giving it a week or so to fully recover.

Root lock isn't that much of a big deal as tons of others say. To me, the root lock plants grow just as nice. If you wanted to get technical, you could say the plant is not reaching its full potential, but I mean you could say that for alot of other factors for a great grow as well (lights, nutrients, LST, Top, Co2, UVB etc)
But I mean as well, if your able to transplant to a bigger bot. No harm there all $$$.

Gee Gee.