That is possible. I don't remember how much I put in. The directions only gave how much to put in a gallon of water, but I just put some in every time I watered it. I probably over fed.
I don't know. I've read on the box you can't overfeed with it.
I've always used one of those miracle grow sprayers that dilutes it automatically. I use it about once a week till everything is good and established, then back off to just whenever I get a wild notion too use it:).
Becky