Where can I buy the dvd of Bloodline season 1
Thanks for asking! Based on some searching, and most concisely covered in the series' Wikipedia page, it looks like none of the seasons of Bloodline have received a DVD release in North America. This is speculation, but this may be due to the series' licensing as a Netflix original series, or due to a licensing dispute with Sony. Sony had distribution rights for the series internationally; the series has been released on DVD in Australia, Germany, and the UK, but unless you have access to a device that can play Region 2 DVDs (highly unlikely for most US consumers) I would refrain from buying a copy of the DVD from online sellers.
Until the series receives a US DVD release - which does not appear to be in the works anytime soon - your best bet to access the show may be through a streaming service like Netflix or Amazon Prime.
Thanks again for asking, and thanks for using AskOPL!