QuestionQUESTION: Hi Wayne, I have some oncidium orchids which I have not been able to get to bloom. I've had them for approximately 1-1/2 years. No problem getting new growth, pseudo bulbs and lots of roots (roots everywhere), but no spikes or flowers. I suspected they weren't getting enough light (they are in a west facing window) so I have put them under artifical light during the past couple of weeks. They look healthy but no flowers. :( Any suggestions
Secondly, I have two orchids which are very small and the person who gave them to me doesn't know what kind they are. They remind me of a dendrobium in that leaves come from a central stalk (which is covered in a sheath) but what is strange is there are roots growing from the top portion of one stalk. These orchids are only about 6" tall at this time and I really don't have a clue what to expect from them. I've not gotten any blooms. What is up with these roots? Also, I have repotted this so it shouldn't need that. Any information would be greatly appreaciated.
ANSWER: Cheryl, you were correct in thinking that your oncidiums need more light. I have a couple at the top of my greenhouse that are just coming into bloom. They also appreciate plenty of warmth and air movement. Artificial light might help at this time of year because natural light, in some parts of the country, is limited due to cloudiness and shorter days. A west or south window would give them the most natural light and that can be supplemented with artificial light. To grow them strictly under artiicial light I recommend the use of a 400 watt High Pressure Sodium light and fixture. They will thrive in an outside location during warm days and you can slowly move them into nearly full sun in the summer.
From your description, it sounds like the two small orchids are New Guinea dendrobium hybrids which are often mass marketed. They have roots that emerge from nodes or joints in the cane-- probably this a way for the plant to spread in nature. If you wanted divisions of this plant, you could cut a cane off just below a node that has good root growth and pot it up. I realize the profuse root growth is a distraction. Again, grow these with your Oncidiums as they prefer similar conditions.
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QUESTION: Thanks for your quick response. I do have fans creating circulation in the area of the oncidiums and dendrobiums and as you suggested I keep them in the same area. Speaking of artificial light, I recently purchased a light specifically for orchids called a OTT-Lite. Have you heard of it? Thanks for helping us novices. I'm sure I will have more questions in the future.
AnswerCheryl, OTT=Lite is a brand name. They are high eficiency lights manufactured to allow the true colors of the indoor environment to be accented. I have not found any of OTT-Lite's products to be produced specifically for plant growing (ie with a prpoer balance of the blue and red ends of the spectrum. However, the most important factor will be intensity. The minimum intensity recommended for orchids is 160 watts and I use 400 watts for high light orchids like oncidiums. The 400 watt high pressure sodium bulbs are available for about $25 but they require a special fixture for the bulb. The good side is that these bulbs last for years. I look forward to additional questions.