Eulophia petersii Eulophia petersii will grow best in a deep pot that accommodates the big root system. Use a coarse, well-drained succulent mix. During the summer growing season, they can take quite a bit of water, but it's best to water only when the medium dries out, about every two weeks. They can go months without water, especially during the cool season. It is tolerant of temperatures from well over 100 F to freezing. All-day sun is a bit too much in summer; the plant will look much better in very light shade. To ensure flowering, give the plant a cool, dry winter rest. While it can tolerate down to freezing or even a few degrees below under a cover, it tends not to flower after a cold winter outdoors or in an unheated enclosure. I keep my plants in a cool greenhouse with night temperatures about 45-50 F. Watering during winter also seems to inhibit flowering. I don't water my plants at all from November until March. Plants are vigorous and will grow into large clumps that bear a dozen or more inflorescences.

 

Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz