chemicals in your yard that might ultimately hurt the frogs.
once you have built the perfect pond, it may take a while for it to become well-established and for local frogs to find it. resist the temptation to catch frogs to put in your pond, as adult frogs have established a home and may try to return to it. if it is legal, you may try catching tadpoles to put in your pond, but check you local wildlife laws as collecting tadpoles is illegal in many places. 