what soil, light, and other equipment are you using? How old are they? Cannabis grows best in temps of 76 to about 84. It is ok for the temp to go down 10 degrees or so when the lights are out. Also bblz is right you need to bring the light closer so they don't have to reach for it. Also, like bblz said, read read read and read some more. Prior to my first grow I read and watched video after video (you tube has a lot of good grow vids) until my eyes bled. There is a ton of great info on this forum. But, don't go overboard as well and over complicate. Nothing has harmed or killed more plants than growers using tons of different nutes, different mediums etc etc and 'loving their plants to death'. Remember cannabis is a weed, it wants to grow. This time it seems you went way the opposite way, just planted a seed in some soil and put a light on it. Consider it a learning experience. BTW they don't look dead, just need a bit of TLC. Cannabis is a very resilient and forgiving plant. Try moving the light closer and if you are using MG soil, do not ad any more nutes until well into flowering.