White Spots On Leaves

I have dill, basil, parsley and rosemary in a large pot under a Grow-Light in my living room. I water once a week, mist occasionally. I used fresh soil but will start with a fish fertilizer soon....
My problem is not bugs, maybe a cold draft or watering. I can't figure it out. Most of my leaves have white spots, all over. Does this sound common to you? None of my house plants have this problem, just the herbs.

I have a suspicion, that the lights on the plants are quite hot. When you mist the plants, little droplets stay on the leaves that act like lenses and concentrate the light and heat on the leaf just below it, more or less in a small spot. The leaf cannot take this and dies in this spot. Because there is no disease, the spot stays white or clear.
If you can rub the spots off, then the explanation is quite different. Then these spots are calcium deposits left behind by the evaporating water droplets. The droplets contract as they dry and end up leaving a small spot of water borne calcium, once all the water has dried off.