The genus Zygopetalum consists of sixteen species from South America. The most commonly cultivated ones coming from Brazil. The plants grow both as epiphytes and terrestials in wet forests at elevations of 1000 to 5000 feet. Most species bloom in the fall.
Between 40 and 85 degrees. While these plants can tolerate lows of 32 and highs of 90 they prefer this less extreme range. They do need lows around 50 to initiate their blooming cycle. This means they can be grown outside in most of southern California.
Bright filtered or indirect light. Outdoors this means under a lightly foliated tree, under a tree which provides afternoon shade, or on the north-east side of a house. Indoors this means under a big skylight, near a east or south facing window.
Usually once a week. However, extra hot and dry weather or a big plant in a small pot can require more frequent watering. The best way to tell when to water is to lift the pot and feel the weight. You want to water the day before the plant is competely dry. When you do water, do it twice as this gives the orchid more opportunity to absorb the water. Water once with plain water allowing the water to run through and drain. Water a second time at least a half hour later with your fertilized water.
Use a relatively balanced fertilizer such as a 7-9-5, 10-5-10, or a 20-20-20. For the first two use a rate of 1 teaspoon per gallon, the third a 1/2 teaspoon per gallon. Urea as a nitrogen source should be avoided.
Repot every two to three years using a mix of half fine and half medium size bark. To repot squeeze the pot while gently pulling on the plant. Next, remove all the old mix as well as any flat or mushy roots. If you choose to divide, maintain at least two to three bulb divisions. Select a pot size which will allow for two to three years growth. Its not a bad idea to allow the new bark to soak in water overnight before using.