Why is my marijuana plant dying?

PI have cut off most the leaves because they were dead and probly stressing my baby out :/ I have a natural soil in a metal bucket like pot ive made 5, 3/16 in. drain holes in the botom I have been growin her out door day and night and take her in when the rain comes id say the average night tempurature is around 40 degrees I am in california I have only forgot to water once and this was not wen I experienced problems id say it was 3 days after that I have not added any nutrience please help me and her! I care for her dearly.