Rebutia fiebrigii var. donaldiana 'Donald's Red Crown Cactus'

early summer. Hardy to 9b (25° F). Rebutia will not survive a hard frost. However, cactus can easily be grown indoors under grow lights or in a sunny window if there is a risk of temperatures dropping below 25° F. If there is only a risk of freezing temperatures for a few days, most succulents do just fine outside if they are covered by frost cloth or a sheet until temperatures increase (I'm talking to you, Zone 9 friends). Rebutia Care: As with all cactus, it is best to follow a "soak and dry" schedule where you water your plants deeply (until water runs out the bottom drain holes), and then allow your soil to dry completely before watering again. Cactus should always be planted in well-draining cactus and succulent soil and in a pot or container that has drain holes.