Treat them mean and keep them keen – a term not often used in relation to plants but in the case of a Christmas cactus its the key to getting then to flower at the best. Ideally they need to be grown pot bound and slightly under feed so the leaves start to yellow in the autumn. This bad treatment of a Christmas Cactus will help induce the plant to flower at its most prolific. Then when its finished flowering in late winter give it a light house plant feed and when the risk of frost has based place the plant out side on a patio so that the summer rains can remove all the dust that builds on the plants leaves over the winter inside