Still have 'em, or did you toss 'em?

Mold only happens if the soil is retaining water too long or if you are overwatering them. (keeping the soil too moist for too long)
Adding extra perlite to the soil, and/or adjusting your watering schedule fixes this problem. Be sure to let the soil dry between flushes, (and watering after flushes) too.

Miracle Grow says their time-release nutrients have all the micronutrients a plant will need, but I'm doubtful that's true. You might want to try unsulphered molasses one a week or once every two weeks. Don't overuse the molasses though. 1 tsp per gallon of properly ph'd water every two weeks, or 1/2 tsp per gallon once a week should be fine during the growth phase.