please , need advise for discolored lime green plant

Hi.
My strain is Jack flash. It is about 2 weeks old. The color is lime green, really light green, comparable to my other strains, which are showing normal green. Could this be caused by this strain, or why this light color ? Along with this discoloration, it has not been growing half the size, comparable to the other strain I´m growing. http://i880.photobucket.com/albums/a...0/DSCF3187.jpg
Another thing is that my other strain - Northern lights, which has been grown at the same time, has started showing in the lower leaves (fan leaves ?), looseness, and distinct dropping, which you can see in the picture I´ve added.http://i880.photobucket.com/albums/a...0/DSCF3176.jpg
What could be the cause of this ? The plant is having small (a few) yellow spots. What could be the cause of this ? Since they are not that old, and due to the transplantation, I have not started giving nutrients yet. From what I have gathered from nutrient problem, this might be due to deficiency in N, or what would you say, or is it temperature problem?? Should I start giving nutrients (with high N level), or is it to soon (plant is little more than 2 weeks old)? I also have Alg-A-Mic from Biobizz, could this be a good time of starting using it ??

Thanks alot for help, highly appreciated.

Jack flash
Northern lights http://i880.photobucket.com/albums/ac4/trobadour_2010/DSCF3176.jpg

What type of lights are you using?
The lighter color of the Jack Flash is usually an indication of a magnesium deficiency.
This is common.
I wouldn't recommend nutes yet however, a magnesium supplement (1 tbs or less epsom salts per gallon water) should bring back the color.


Your Northern Lights looks ready for whatever nutes you have.
I usually use a weaker concentration than suggested the first time to be safe. (small/young plants don't recover from nute burn too well)