Potting Media for Oncidiums

[atcrosby]

Okay, I think I figured out what the issue is with my Oncidiums and though I would throw out to the collective wisdom what I should do.

I have been successful in keeping my oncidiums alive but they're not thriving. The roots stay in the top third-half of the pot. I have notices the bottom tends to be pretty wet. These plants sit on top of humidity trays so I am thinking that's what's throwing them off.

The plants are in azalea pots with holes in the bottom. The medium is bark or a bark/peat mix for the Phals. I am thinking I may have some options:

Option 1: Change planting medium to something inorganic (aliflor) so that it'll dry out faster

Option 2: Change pots to plastic orchid pots with slits. I have also seen the Aircone where there is a cone to increase the airflow to the underside of the plant.

Option 3: Let the medium totally dry out even if the top is dry.

None of my plants seem to be dying off but this is the fourth time I have repotted a plant and find it in this condition.

Thanks.

[Cynthia, Prescott, AZ]

How big are the azalea pots. Bulb pans come as small as 5" diameter, but they are probably hard to find. The smaller the pot, the faster they dry. I am using a mixture of 3 parts small perlite to 2 parts Candian peat with a little E. B. Stone dolomitic limestone thrown in. When this is pressed well into the pot, it wicks thru the pot and never is wet at the bottom while dry at the top. I think many mixes may be like that, in that you have to pack them well to get wicking. When I pot into bark, which I will do these days if the orchid is going to someone else, I always do a good packing job, so that the plant is very firmly held by the mix. Maybe that is your problem. Cynthia

[atcrosby]

The pots are 3 or 4 inch pots depending on the size of the plant. The mix is a combination of Bark and Charcoal so no sure what you mean by packing down. Do you mean pressing down on the medium? The bark is coarse and doesn't lend itself to packing down so that's why I am confused.

[mayres]

Tom - in the for what its worth department - I have my oncidiums in fine barak with perlite and they seem to be doing very well in it. I do try to keep the pot size as small as possible at all times so as not to have large areas with no roots. mike

[Cynthia, Prescott, AZ]

The bark needs to be pressed into the pot. When you have finished potting, you should be able to grab hold of the plant and lift it gently without the pot and mix falling away. That is what I mean by the right way to put bark or any other mix into a pot. And yes, it is a bit hard on the roots, so it is a bit of a trade off, just enough pressing to acheive the effect above, but not so much to do major damage to the roots. Try to work the bark in so as to not cause a major bending of the roots, but they will usually bend a bit without breaking. And I agree with Mike, I would normally recommend small or fine bark with Oncidiums. Small roots get small bark, and fine roots get fine bark. Cynthia