I recommend that you adjust all post dated checks beyond the month of preparation of financial staements. This is because that even though you have issued the checks, your suppliers cannot present them to the bank as payment for your account within the period. Therefore, in my opinion, it is just right to recognize the liabiltity account for the period assuming that you have entered the checks already in your cash disbursements book.
Entry per CDB: Accounts Payable XXX Cash in Bank XXX To record check payment.
Adjusting Entry: Cash in Bank XXX Accounts Payable XXX To adust entries for post dated checks.
Im assuming that youn are using accrual basis of account or voucher system.