Oncidium in bark--self watering for me?

[irrka]

Hi! i bought an oncidium (vuylsteakara) that was potted in bark so i just left it in that medium. (after adding some new bark after it got toppled by clumsy cat). The thing is sitting in a southern window. Leaves are green. It gets watered every week or week and a half and is on top of a little water tray for humidity. But it just WON't send spikes out. Any suggestions? I thought maybe putting it in a self watering pot, but would bark draw too much water and rot the roots?
thanks for any suggestions.

[Orchidophile]

Hello, I think the self watering pot would keep the roots constantly moist or wet and it would eventually rot. I'd say to just leave it in the pot its in for a while. It might not be getting enough light to send out spikes.

[irrka]

I thought so too, but then you have the whole s/h thread with everyone's plants' roots constantly moist, right?

[Ray]

That's right. Water, by itself, does not cause rot. Almost all of my collection is in S/H culture, so stay constantly wet. The oncidiinae intergenerics, like your vuylstekeara, absolutely love it. Plants have also been successfully grown in water culture, with the roots totally submerged and having no other medium present.

However, there are some caveats:

• The roots tailor themselves to the local environment in which they grow, then don't change. If the plant has grown its current roots in the dry bark environment, they will not function well in the wet one, so it will have to grow new roots to take over, as the old ones will die and decompose. That's why it's important to time repotting to coincide with new root growth - so those new roots will tailor themselves to the new environment, taking over the support of the plant as the old roots slowly fail.
• If the potting medium is too fine, water droplets will remain suspended between the particles by surface tension, cutting off the air flow, stifling gas exchange, and potentially suffocating the roots to death. Then they will rot. (This, by the way, is the source of the misinterpreted observation that "too much water causes root rot". By allowing the too-fine medium to dry out, those droplets disappear, and the air-flow channels are reopened. If those pathways are larger, as with a coarse-grade medium, droplets cannot block them completely, so there is no need to have the medium dry out.)
• Keeping an organic material like bark constantly wet shortens its life, so it will decompose more rapidly, becoming more compact and finer in overall particle size, leading to the conditions I mentioned above. It is preferable to use inorganic media if you're going to keep it moist.

Of course, water and potting media might not even be playing a role in you plant not blooming. Your light levels are probably OK, so what's your feeding regimen - formula used, mixing ratio, and frequency?

[irrka]

Ray: thanks for the explanation! that absolutely makes sense.
I've just been feeding super-dilute Shultz stuff (pink granules) from HomeDepot every time i water. And by super dilute i mean maybe a few granules to a quart to half gallon.
Wrong food? Too little food?

[Grandma M]

I grow my oncid. alliance plants in S/H and they love it. They grow like crazy and every one blooms. I only have one in bark mix, because the plant is so large I could never move it if it were in S/H.

[Ross]

My Vuyl. gets watered every 5th day during winter and the top of the mix sprayed with water (RO) to encourage new root growth - which is working. Mine is in a south bay window with supplemental CF lighting to up the anti (so to speak) and is doing quite well with new growths. Too early to tell if they will bloom, since the Vuyl. are pretty slow growers, by-and-large.

[Ray]

Probably too little food, irrka.

Personally, I recommend dividing 10 by the %N on the label to get the teaspoons per gallon to use.

In semi-hydroponic culture, I water with that solution every time. In organic-based media in standard culture, I would do so three out of four times, with that 4th being plain water to flush the medium.

[irrka]

Thanks, Ray! I will try that!

[irrka]

http://picasaweb.google.com/irrka1/P...70868105908802
here's what it looks like by the way