Brown spots on Oncidium
 

My office building changes out the orchids in the common areas each month and has recently begun to offer to the tenants the old orchids. I've picked up 3 - 2 Dendrobiums and 1 Oncidium varicosum. I scoured the internet looking at pictures to find orchids that looked like the ones that I have, so I can't get any more specific on the type of Dendrobium. However, I'm pretty sure the Oncidium I picked up is Oncidium varicosum. I'm currently at work and do not have my camera, otherwise I would post a picture. I'll try to remember to do that soon so you can see what I've got.

On to my questions....

The Oncidium is still flowering and it's lovely. The psuedobulbs are pretty shriveled, though. Is this normal? If not, what should I do? Soak? If so, how long and how often?

Also, one of the pbulbs has just one leaf and it has brown spots all over it. (Note that all leaves are green and appear to be healthy, except for the spots on this one leaf.) What is causing these spots?

One of the Dendrobiums looks very healthy. It has one large cane with six leaves, all healthy-looking and one very small, older cane that is very soft (no leaves). Is this small cane dead? Should I remove it? Oh, and there are 2 new shoots (lack of specific term) coming from the base of the larger cane. They each have 2 leaves with a 3rd growing. I just cut the flower spike on the large cane to about 1/4 inch. Overall, I think this plant is in great shape, I just don't know what to do about the smaller cane.

The other Dendrobium appears to be the same type as the one described above, however, it looks less healthy. It has 2 large (tall) canes, and the tallest of the 2 still has one flower left on the flower spike. However, this cane has dropped all of its leaves - it had 2 when I got it a week ago and both have yellowed at their base and fallen off. The other cane has 2 leaves and both look healthy (the flower spike was cut to 1/4" before I got it). Please advise on the leaf loss and watering needs.

Currently, all three orchids are growing on my desk, which is walled by an east-facing window. I leave my blinds open all day, so they get quite a bit of light, but only a little direct morning sunlight. I would rather keep these guys here at the office as my cats at home will try to feast on them and I don't really have a lot of windowsills at home that get adequate lighting. In the summer, I can put them on my back patio which gets filtered sun throughout the day; however, it's already in the 50's at night in Dallas, so I think leaving them outside is out of the question. They are inside for the winter.

Oh, I almost forgot...all 3 plants are potted in 4" pots in bark medium topped with spagh moss. I was going to wait to repot them once they stop blooming (which I can do for 2 of the 3 right now just havent gotten to it yet), so I have not had a chance to inspect their roots.

Thanks!
Mary Helen

I am by far no expert & I can't really comment on the Dens but I can tell you what works for my Oncidium. Oncs like lots of light I have mine hanging in a southern facing window. An east window will work as long as it's bright. I would move yours closer to the window so it will receive higher light than the Dens. Oncs also don't like to dry out and the pbulbs should be plump. A sure sign to water is shriveling pbulbs. When I water mine I soak it in a bowl for anywhere from 15 to 20 minutes. Within a day or so the bulbs plump right up. I water mine pretty much like my Phals. When the medium is almost dry and the pot is way lighter. I use a bamboo skewer and leave it in the pot and pull it out and check the moisture. It will feel wet/really moist/moist/almost dry/dry. The color will also let you know. I sometimes place it on my cheek if I have trouble telling. If it's cold/cooler the plant doesn't need watered. If its warm/not so cool and barely moist, it's time to water. I'm sure if you do a search on skewer you will find a more detailed thread for using that method.

Also her are some links to the AOS's culture sheets for Onc's and Dens:

Onc:
http://www.aos.org/AM/Template.cfm?S...ContentID=6852

Den:
http://www.aos.org/AM/Template.cfm?S...ContentID=6847

Thanks Breezy! The pbulbs are very shriveled and pruny. I will soak it this afternoon.

It's still blooming but I'm wondering if it's worth repotting it to check the roots to see if they are also a part of the problem. Anyone have any thoughts on this idea or should I just keep with the plan to soak the plant each week (or more often?) to try and re-plump the pbulbs, and then re-pot once the bloom cycle is over?

I would at least pull the plant a bit out of the pot it's in and have a look at the roots. If they look good (white/green and firm) I would leave the plant in the pot until it's finished blooming then repot. If they aren't looking so good (brownish and soft/squishy) I would go ahead and repot. Make sure that you soak the medium a good 24 hours before using it. It helps with moisture retention.