a little help please

[Jeanna]

New here, and I could use a little help diagnosing my problem. Two of my girls have started turning yellow on their new growth one of the girls the yellowing might be taking over the plant :( I am worried that they are either to cold or lacking some nutrients? They are in the garage in a grow tent with a 400 MH and i have had them on water only for the last week due to some yellow tippage i thought may have been from over fertilizing. They are currently vegging. Should I get a 1,000 watt or do i have a nitrogen problem? Any help would be greatly appreciated. I have included pictures of my girls with the problem.

http://farm6.static.flickr.com/5242/5286511426_857e11f14d_b.jpg

http://farm6.static.flickr.com/5208/5285910915_3573cf0593_b.jpg

http://farm6.static.flickr.com/5002/5286509294_62a1391307_b.jpg

http://farm6.static.flickr.com/5127/5286508142_1ce2ab4637_b.jpg

[Rusty Trichome]

Could be rootbound, could be overwatering, could be calcium deficiency. Fill-out the troubleshooting form. (copy-paste and answer the questions) The link is available in my signature.

Hope ya have a Merry Christmas. :thumbsup: