Justin I know the product you are talkng about, fungicide 3 by gardensafe... I have OD'd on it too lol... you can suffocate your plants by overapplying the stuff.

Small seedlings are VERY VERY delicate when it comes to sprays so keep that in mind.

Miracle gro? Jacks classic you mean? I have been happy with the Jacks in the past. They have a good variety of nute ratios and a nOOb can do far worse for an easy to find fert. Just go REAL easy on it, starting at less than the recommended dosage, until you see how the plants react, and no feeding before 5 nodes!!!