What happened to my plants??

[temoshi]

I currently have a 250w HPS setup in a small closet grow space. I am using Fox Farm soil and Pure Plend Pro Grow nutrients from Botanicare. The space is pretty well ventilated, and the temperature stays around 75-80 degrees, with the humidity usually between 50-60%.

I have 24 plants that are about four weeks old, which have been doing very well up until now. They had all been in small pots like the first two pictures. I was away from my house last night, but I had watered them the night before. I came home earlier today to find my all of plants had all shriveled up and were drooping heavily (like in the first two pictures). They still looked very green, but they had shrunk considerably in size. I knew they needed to be watered, but they had only gone less than 48 hours without water and I didn't think they would be in this bad of shape. I gave them all a good watering and within a couple of hours, about two thirds of them had perked back up to their usual appearance (like the plants in the third picture). Clearly, lack of watering was part of the problem, but I'm wondering if there wasn't also something else. I examined the plants with a friend and we found that they were starting to get "pot-bound". So, we took the healthiest plants that had sprung back and transplanted them into larger pots (around 1 gallon).

Currently, I have 9 healthy-looking plants that have just been moved to larger pots to give their roots space to grow in. About seven more are still in small pots, but are doing well. Another 8 of them are still looking wilted and sickly. Chances are that some of them will have to be destroyed for lack of space, but I'm trying to figure out what caused this. The 8 sickly-looking ones have very little rigidity, and have fallen over (like the first two pictures). Is it possible that the plants had used up all of the available nutrients in the soil while in the small pots and were not being sustained by the plant food alone? Or was a day and a half simply too long to go without water and they started to die?

Thanks in advance for any advice.

[TexarkanaTim]

Your plants are too big to be in pots that small. Your only problem is that they are root bound. The soil cant hold enough moisture to support the amount of roots they have for very long, and this will eventually cause nute deficiency also. If you can transplant into bigger pots, they all should survive. You are kind of at a point where you need to decide if you want to keep them all or cull down to a smaller number of plants.