Hello! I planted tomato from seeds about 3-4 weeks ago...great germination and good looking seedlings. I transplanted into bigger peat pots and they did well at first...with no apparent problem. But now most of my plants are very dark green...and lots of purple. They don't look bright green and healthy like they did. Some of the leaves are also slightly wilted. They are under florescent lighting...and the leaves aren't yellow so I don't think it's over watering. Could too much light do this? I work nights and the tomatoes occasionally get 24 hours of light at a time as I forget to give them their 6 hour break. Also, at this point, do they need any sort of fertilization. They are in Jiffy planting mix.

Thanks so much in advance!