Leaves drying out and curling upward?

Alright so I have 3 plants under one 96w T5HO and a 28w CFL.
I put them into flowering after 3 weeks of 18/6 growth just to experiment.
I fed them once or twice with nutes with a 4-3-3 ratio and then switched to 2-4-4 when I put them into flowering. Now its been almost 2 weeks into flowering and they were starting to smell real nice and everything was going great until last night. About an inch of most leaves were dry and curling upward and I was surprised it got that bad over night so thats why I can't figure out what it is. I'll post pictures of them now and the night before, anyone know what could be the cause of this? I'm not sure of the humidity of the room but the temperature is around 75.

Only a guess here but I had that happen to two of my girls.. have one in the veg cab now doing exactly the same and I am putting it down to the compost I got from the local garden centre being a tad too hot for them.. so for me its back to the BAC lava soil.. .. my guess is the soil being too hot they also look overwatered.. but I am fairly new to this growing indoors malarky so could be way off, will pull up a chair and see what other more experienced peeps say as I would love to know the answer to this one.. I did once think it could be heat stress but your temps are very similar to mine.. they do come back though... yield is effected but..they do come back... our wee plant is one tough lady.

would help peeps lots if you can tell us what soil they are in.. how long they been in the pots etc

Leaf curl is almost always an indicator of nutrient lock or nutreant burn as its often called. its realy a shame this happend to you ladys in flowering...this lil prob is going to dramaticly reduce potience and yeild...it would honistly be best to toss the plant and start over.. if you just cant bring yourself to do that then...revert your ladys back to the veg light cycle 18-6. clip off and leafs that are over 50% yellowed or brown and lightly flush the soil..IE pour water into the pots untill you start to see water comming out of the lil holes in the bottom of the pot count to 3 and stop pouring water. feed only water for one week and resume normal nutriant feeding at half strenth. ALOT of those blooom foods out there nute. lock plants..you should always feed nutes at half or quarter strenth.. actually you should grow organicly..but anyways.. like i said if you girls pull threw they will yeild poorly and the potiency will be low...the nute lock and changing of the light cycle is going to realy stress your ladys out...it'll take at least two or thee weeks before you'll want to put em back into flowering..it would be alot smarter of you to start new plants.. sry somtimes learning is costly... also i should mention the somtimes leaf curl can be a genetic condition that has nothing to do with nutes. but that is not the case here that bloom food screwed you over big time. sry bout your luck..hope you have a better go of things on your next grow.

alright buddy let's see of if i can help you

firstly, whats the run off PH? judging by the numbers on your nutes (4-3-3 & 2-4-4) i'm gonna guess they are organics? i remember before i went organic, the numbers were higher like 15-30-15. that being said, its very hard to nute burn your plants with organic nutes. however, if you are having PH problems, some nutes wont be available (regardless if u give them to the plant of not) because of the PH levels.

it really doesn't look like heat stress/burn. as far as the lights, you can do an entire grow with CFLs, one of my earlier grows pulled ~120g off a single plant with nothing but strategically placed CFLs. one thing to remember is that CFLs can be very close to the plants (unlike MH or HPS), but again this problem doesn't look to be caused by your lights.

just get your PH fixed to 6.4-6.8, and then dial it in from there based on how the plant responds.

and lastly, before u go adjusting the PH, make sure to flush the plant pretty good, think 2 gallons water for each gallon of dirt. and no not worry about drowning the plant. to over water, you'd have to water every day and not let the roots dry out. but if your roots are dry, you can dump as much water as u want through the medium as long as you let the roots dry out again before you water it again.

hope that helps, i'll try to check back if you have more questions.

Good Luck!

Thanks a lot man I'll give that a shot, I figured it couldve been a pH problem but this is my first grow. I switched nutes without flushing and I actually haven't flushed them yet but I'll definitely do it text time they need water

Bigger pots