If that is an hps bulb then I think it is too close to your kids. I started my new babies with the light several feet away (I use a 1kw) starting at about 4 feet and bringing it down a foot every 4-5 days. I don't know about your watering technique--whether the top of the soil is drying out due to the light and underneath it is wet or dried out altogether. Don't let the soil where the roots are get dry or it will kill off your roots. As for nutrients, I generally go with 1/3 strenth at first and go up but that is for hydro. I'm useless when it comes to soil.

PS If that light is shining on those plants after you have sprayed them (especially at a few inches away) you will cook your plants.