Chem help needed

Cleaning out some crap from my closet and found some stuff that probably hails back from my high school days. There was a crystal growing kit (sans instructions) that I want to make sure I can get rid of without dumping hazardous materials where I shouldn't.

They're sealed bags of monoammonium phosphate, NH₄H₂PO₄.

So, can I dump this down the drain? Do I dump them in the trash?