SHALL I REPOT THESE ORCHID PLANTS

[Bud]

you got sound advice from everyone on this thread....but when you repot make sure to spray hydrogen peroxide or physan20 to rule out bacteria/ fungi infestation....you never know

[Chatbud]

Originally Posted by james mickelso

I say don't water them until repotted because they reside in Singapore and they look to be potted in sphagnum moss which retains a lot of water and down inside the moss stays wet for a long time. And the black rot is indicative of wet conditions. These don't need water. Catts start to get wrinkled pbulbs when the new growth starts to take water and nutrients from the older pbulbs before they get new roots growing. I have a few cats that stay somewhat plump but most start to shrink once the new growth gets half mature. That's what the older pbulbs are for. Just the look of these tells me they don't need watering but need to dry out. Singapore is very humid and wet at certain times of the year.

The observation about old bulbs and new growths - does it apply to dendrobium phalaenopsis too?
I have 4 pots of den. phal. that get splashed with full sun from 1-4pm (dappled light in the morning cos they are under the foliage of a larger plant).

The older canes shriveled noticeably but the keikis are all green and full. Could direct sun cause the shrivelling?

[james mickelso]

Catts, Dendrobiums, and most any other orchids do not take full sun. Unless they are under some sort of cover even a tree and have shade on them, they get sunburn very quickly. If the tree is very tall and the dappling is moving all the time, they could still get sunburn. The shrivling is due to bad roots or being too dry. the bad roots can't take up enough water to keep the plant hydrated. Send pics of the plants. Pics of leaves and tops of pots.

[james mickelso]

Also the canes of the dendrobiums shrivel because they are supporting the new growth which have no roots yet. Same with catts/laelias and many other orchid types. The old canes (pbulbs) move their water/starches/sugars to the new growth as it emerges and before it puts on roots of their own. It is normal.

[nlm2951]

I also remove with a soapy water and tooth brush that brown cover of the pseudobulbs, scales get in there, and destroy it, after use alcohol