bdt- that HPS light might be part of the problem, being too close, too hot! - raise it up several more inches.... the plant is stressing over keeping itself cool, moving all that water up there to trying to regulate Temps,... RH plays a big role in this as well, as does air circulation... even with moist soil, wilting can happen, if it's combined with low RH and too strong of air circulation... don't like the looks of the plants color either-- how are you getting pH readings, and what are they? (Fweed and Trap have your good tip covered there already!)....good points made about wilting-- funny, both too dry and too wet cause the same thing! MJ wants to be fairly moist, more consistently during veg' in particular; more wet to dry cycling during later bloom is fine... So, you say she improves after a watering?-- that's means things were dry, deep dry!....(one thing to watch out for: sometimes, the surface soil will be much drier than down deeper, but folks will give a big drink anyway, instead of a lighter one, which can lead to overwatering as well; avoid extreme swings between wet/dry, as this can make the pH swing too... if it's borderline, matters can potentially worsen...); as mentioned, hefting the pot can tell you overall how moist it is, but you need to calibrate yourself, getting a feel for the weight when it's well watered, and then when it's on the dry side,.. but in any case, try not to let it get to the point of wilting! get us temp, RH, pH readings, and tell us what's up with your air circ., namely, how much of a breeze are the plants experiencing,..