I would shy away from doing this. The bank has no obligation to uphold the post-date that you write. I once sent in a post-dated rent check that was dependent on a deposit clearing, and the landlord (accidentally) brought it in earlier and it was accepted by the bank. Luckily, the bank covered it for me, but I still had to deal with overdraft fees and such. The bank manager explained to me that post-dating is typically honored by a bank.