Is a spot that is covered in moss good to grow in??

Say i found this spot that is covered in moss and a bunch of 9 foot birch trees..the soil underneath is black and nice and rich with a ph of about 5.5 or so...it holds water quite well but is in a spot that could easily flood (flat ground)

what should i do to give my soil better drainage ( add some sand?) or what?

Sounds like its a damp spot, I wouldn't grow there. Sand will help increase drainage for certain.

sounds like your in a vernal pool area look it up online, in spring and early summer this spot will be a bit wet aka flooded. beginning to mid June this location should dry up and remain at a constant moisture level. as for the birch trees, clear the limbs directly above where your putting each plant so that light competition is in the favor of your babies. if your still a bit worried about flooding then only put a few of your plants here, if all goes well then you know what to expect from this spot next year.

well its not quite a vernal pool it is about 30 yards from a small bog and it does have a chance of flooding probably ( northern maine)

and has anyone tried lowryder for an outside grow?

would perlite be ok to add to my outside grow soil?