Can you get a better picture? With the light it looks like it could be too much nitrogen. What's your set up? Soil, nutes, etc. Are you using a PH meter?
A Potassium Deficiency will cause your leaves to turn a lush Green, Nitrogen Toxicity will also to the same thing.
If the plants been in the same container for a long period of time you can get salt build up in the soil lowering your pH
To Much water can also get you into alot of problems. Messing up nutrient up-take.
IMO- You need to know your pH, you might have to add some lime.