leaves curling and drying out

im having a problem on my plant. the older growth is curling, then drying out and becoming crispy. is the light too close? not enough water? im running a 400w hps and plant was probably 10-12" from the light, but i moved it to 20 or so earlier thinking that the light is too close..

400w 50cm from plant tip at all times u may get away with 40cm, a way to check is put ur hand ontop of the plant and if slightly feels like its burning or lil to hot then its also 2hot for ur plants ok, cant realy tell bout ur plants tho without pics!!

i did the hand trick when i first set it up and it wasnt hot, but i did feel the warmth of the light, but i figured that that was the problem..thanks for the confirmation

+rep

i,m having the same problem with my plants except more severe. i am about 95 percent sure one of them is a goner and the other isn't looking very good either.
i have limited grow space so i decided to just turn the light to the ceiling and reflect it with white paper after realizing that they were drying out. it doesn't feel too hot inside.
but they are still drying out. i spray them a few times daily one of them i don't use Any nutes on. i just put cups transparent plastic cups over them to try and retain moisture.
does anyone know what the problem is?
btw i do not have good airflow into my setup at the moment. could that be cntributing to the problem

U shouldnt even think of growing without air air+water+light 3 most important for a plant to grow.!!
Good airflow is a must dude.

Get a lil fan blowing in there at least man!!

Yeah a fan do the job, i have a 1000w in a 4x5x5 area with a big fan circulating the air, my plants are at 24" from the top of the plant and seems to be ok... one shown lil burn.. but found that she did not get watered properly tough... The room temps stay at 80-85F...

got a fan in there now. problem doesnt seem to be progressing to the new growth so maybe its bc of that or the fact that its been pretty cold lately...lol