Looking at the plants all I can say is start over. First thing I would do is flush the soil with clearex(sp) It will clean the dirt and clean any salt build ups on the roots. Then test the dirt for fertilizer. A cheap kit can be bought at any horticulture store. Look at results and adjust as needed. One thing to consider....set up a hydro unit. Its easy, cheap and can make things like this in the past. I have been doing this for about 35 years and hydro is the best way. Any mistakes in hydro can be fixed within 3 days, soil takes weeks sometimes.

Your light source is too small also. You will need to keep the light close as possible to plants for best result. I could go on but first try Clearex(sp).