111:13 If one converted a room for storage with the intention that he will not empty it out until after Pesach, then there are different scenarios depending on the timing. If it is more than thirty days before Pesach, he does not need to check it, though if he knows there is definitely chometz there, it must be removed beforehand. His nullification is effective and he can nullify all the chometz at the usual time. If it is within thirty days of Pesach, he must check the room; this is because one delves into the laws of Pesach for the thirty days prior. If he forgot and didn’t check this room, he must empty it out and check it at night as soon as he remembers. This is true even b’dieved (after the fact).
111:14 If one stores wheat that is not chometz in a pit and the dampness of the pit causes the wheat at the bottom and the sides of the pit to become chometz, it is not necessary to empty the pit on the night of 14 Nisan to check it, even if the wheat was stored there within thirty days of Pesach. Rather, it is sufficient for him to nullify the chometz because when he stored it, it was done so permissibly. If some of the wheat became chometz, there are other ramifications and a Torah scholar must be consulted.