- 1). Plant epiphyllums in a fast-draining soil mix, such as one used for orchids. Epiphyllums, like orchids, are epiphytes, meaning they grow naturally above ground in the moss, mold and soil collected in the forked branches of trees. They have a vining habit, with a tangled mass of roots and stems that holds the plant in place on the tree branch.
Epiphyllums bloom better when slightly rootbound, so keep them in small pots. Add a trellis or stake to support the vining growth. They also do well in hanging baskets, where they can droop over the side.
Although they have similar growth habits, there is no family relationship between epiphyllums and orchids. Epiphyllums' old nickname of "orchid cactus" has fallen out of favor because it confuses people into thinking they are a kind of orchid. - 2). Give epiphyllums bright, indirect light or filtered sunlight. A bright north or east window is good. Outdoors, they like being hung in trees, where they can get dappled sunlight.
- 3). Water thoroughly, until water runs out the drainage holes of the pot, and then don't water again until the top third of the soil in the pot is dry. Check every few days. Epiphyllums need moisture but will rot if they sit in wet soil. Be careful not to overwater.
Like many jungle plants, epiphyllums like high humidity. Mist them frequently.
Epiphyllums have growing periods in spring and fall, and prefer more water at these times. After their spring flowering, they are resting and need less water. In winter, they need only enough water to keep the soil moist. - 4). Fertilize epiphyllums from spring through fall with a balanced fertilizer, such as 6-6-6 or 8-8-8. Do not go higher than 10-10-10, or dilute a stronger fertilizer to bring it down to these levels. Do not fertilize at all in winter, when the plant is resting. Too little fertilizer is better than too much.
- 5). Don't move plants with flower buds, because the buds can drop off. Buds are formed during long, cool winter nights. Cooler temperatures and more hours of darkness with no artificial light will encourage them to bud. Buds are formed in nodes at the ends of the "leaves" (actually flattened stems).
In this species, flower buds are as large as a person's hand, and opened flowers are as large as a person's head, as much as 10 inches across.
Source...