Night-Blooming Cereus (S. grandiflorus) grows best from spring to fall with night temperatures between 60-65 and day temperatures between 70 to 85. In the winter, temperatures between 50 to 55 at night and under 65 during the day. Higher temperatures in winter prevent bud formation. The plant can be planted in a mixture of 2 parts peat moss, 1 part commercial potting soil and 1 part sharp sand or perlite. Keep the soil medium evenly moist and fertilize every two weeks from spring to late summer with a low nitrogen house plant fertilizer diluted to half strength. During the summer move the plant outside and mist it each week. For rest of the year, keep the plant fairly dry and do not fertilize it. The Night-Blooming Cereus is not that attractive when it is not in bloom, but it will make up for it when it does bloom.
The Creative Gardener