Oh, when you said topp soil, I thought you were growing outdoors.
-I just re'read and saw your lighting watt post.
Your using the wrong dirt, what you can do is mix with sand and perlite and check PH levels weekly, buy plant food.
Personaly, I'd ditch it and get potting soil because of the nutes and really no need to check ph levels for awhile, since you don't need to feed.

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"Years ago, my mother used to say to me, In this world, Elwood, you must be oh, so smart or oh, so pleasant.' Well, for years I was smart. I recommend pleasant. And you can quote me." Elwood P Dowd.