Question
Good day, I bought my oncidium with 3 spikes and last year and this year, only one spike emerged.  The pot is very crowded and it grows outside -in Johannesburg SA - along with dendrobium, and cymbidium and all others are blooming well. I bought a Polystachia and miniature cymbidium last year, both in bloom and this year no sign of any flowers. Is there something I am doing to prevent the flowers?  Many thanks in advance.  Sharon

Answer
Good day, Sharon, and thanks for your question.  First, to the oncidium.  Does it have a name tag?  As with many orchids, some oncidium species, while they may be equatorial, grow at high altitudes and prefer cool temperatures.  However, most hybrids and many species prefer warm temperaatures and bright light.  I will assume that yours is of the latter type as they are the most common. Light is an important factor in flowering.  When you have new growth starting, I would repot it into a larger container in a fir-bark based orchid potting mix.  The container should be well drained.  In unpotting your plant, rinse the roots thoroughly, check for mushy or stringy roots as these should be removed prior to repotting.  Your leaves are good indicators of proper lighting.  If they are dark green, the plant receives insufficient light for best flowering.  If this is the case, gradually move the plant to brighter conditions.  As it adapts to increased lighting, it probably can tolerate full sun for increasing lengths of time. When the plant is puting on new growth, feed heavily with either a balanced (eg 30-30-30) or high nitrogen fertilizer (eg 30-10-10) with every watering.  If you have repotted in a coaser grade or orchid potting mix, you may water and feed once a week. When you approach bloom season, switch your fertilizer to a bloom booster (eg 10-30--20). Most oncidiums tolerate a wide range of temperatures but the warmer types prefer 60-85 degrees F..

Polystachya and the miniature cymbidium prefer intermediate temperatures and light. The two most common polystachys grown where I live are the species galeata (yellow-green-red flowers) and paniculata (orange,yellow,red flowers).  Again, be sure your potting mix is in good condition and follow the feeding schedule I outlined above for the oncidium. They can do well with morning sunshine from an east window or under artificial lights if grown indoors.  They can do well outside when temperatures are in the 60-85 degrees F. range and prefer light shade or dappled sunlight.