Epiphytes and Orchid cacti should be in a light and airy position all year round, in general most succulents should have some sunlight falling on it for some part of the day such as an East (morning sun), South (all day sun) or West (afternoon sun) facing window in order to keep it looking healthy. A north facing window with no sun due to obstacles such as trees, buildings install a plant lamp or put plants outside for the summer. A North facing window is suitable for Rhipsalis and Epiphytic cacti such as Christmas cacti. These plants benefit hugely from spending the summer outside, in fact if these plants have a brief holiday outside they would flower better.
Jungle cacti or epiphytes epiphytes such as Orchid cacti should never be allowed to dry out. However during the Winter, October to March -generally no watering is required at all unless kept Plants are kept in a very warm environment (e.g. rooms with central heating) – then a little water may be required to prevent shrivelling. Rain water (which is slightly acidic) is always better than tap water.
Although most succulents are tolerant of very high temperatures and full sun they will only survive if there is plenty of air circulation e.g. an open window or door, this is imperative as cacti will start to ‘cook’ at 45C. Most are also happy down to about 5C.
It is a myth that cacti only flower every 7 years, once grown to flowering size which many reach after two years they will flower every year and sometimes twice a year. If a flowering cactus does not produce results it will be because the cultural conditions are wrong.
To obtain flowers from an Orchid cacti they need a cool dry rest period in winter, however for Orchid cacti this restperiod is best a week or two after flowering put them in a cool room. After this rest period, if given plenty of good light they should flower on a windowsill. Flowering is greatly helped by regular feeding use a high potash fertiliser (tomato fertiliser is ideal) in the growing season. A plant that is over-potted will put its energy into filling the pot and not making flowers.
Do not over pot, keep plant in a pot that is only a little larger (ideally one size larger only), and repot only repot when the plant touches the rim of the pot or becomes unbalanced. Use a gritty, porous well aerated compost for repotting such as John Innes no. 2 with about 30% sharp sand /grit added.
(Original information source the Cactus Shop)