I did a fishless cycle with plants and found the added ammonia was enough nutrients for me. I just added a little bit of Flourish Comprehensive every once in a while. But if you were seeing bad growth/obvious lack of nutrients in the plants I don't imagine anything bad happening from dosing.
Edit: Didn't see you just had playsand. I would probably throw some root tabs in regardless and dose water column if that's what you were planning on doing later on anyway.