Rotted back bulb on my Onc. Sunny Daze 'Hilo Bay' - Orchid Board

Lady Tottington · #1 07-11-2010, 03:29 PM

Hi friends! Well, I was doing the weekly watering, and got my Onc. over to the sink and just was curious as to how the bigger pseudobulb was doing... so I gently felt it, and it went squish. Eeew. So, I removed it from the plant (which now looks like this). Anyway, why generally, would an older backbulb/pseudobulb rot like that?

I have had this plant for about 3 weeks and realize that I have this over potted, and will fix it today

but at the time I got it, I didn't have anything other than this one.

Eyebabe · #2 07-11-2010, 03:38 PM

Sphag moss is not ideal for these guys.
The current pseudobulbs look also a bit shriveled.
I would be concerned about the root system.
Repotting is right on track imo.
I would presoak a medium bark mix in some rooting solution. If you have a bit of Physan 20 around you could give the plant a treatment with your repot.
Oncidiums are pretty resilient and should do well.

Lady Tottington · #3 07-11-2010, 03:45 PM

the spag is just on the top, and I have a great bark underneath... would you suggest that I remove the spag from the top?

Eyebabe · #4 07-11-2010, 04:45 PM

Quote:

Originally Posted by Lady Tottington

the spag is just on the top, and I have a great bark underneath... would you suggest that I remove the spag from the top?

If the pseudo bulb rotted, it was either because your roots were not good OR the sphag held too much moisture close to the bulbs. Given the bark is in good condition, I'd get rid of the sphag or at least decrease the amount near the bulbs.
My oncidiums and similar types are prone to classic Erwinia seen as brown spotting and rot of the base of the leaves as they attach to the bulbs. Less watering and moisture around them usually clears it up.
OrchidWiz doesn't list sphag as a potting material with oncidiums, they list fir bark. They are suppose to be watered "just as the media is dry". Humidity requirements are a range of 30-60%...so they don't need the sphag to retain moisture imo since 30% is pretty darn low.
Because they have small roots, they are usually more tightly packed in the bark mix(and they are usually potted in a small/medium size mix) and need much less frequent watering than a phal or catt because the finer media retains more water for them.
I am certainly no expert but I am well read

...and the little oncidiums you bought are really, really nice

Lady Tottington · #5 07-11-2010, 05:24 PM

Thanks D! I will repot in a smaller pot and find some of the smaller mix and lessen the spag on the top if not remove all together if I an find smaller bark mix. Thanks for your help!

Lady Tottington · #6 07-11-2010, 06:10 PM

what sort of rooting solution? given that I don't have any, I will need to get some... but we only have a Lowes & HD... would they have it there?

I did take out and have repoted and cut off dead roots (where the mushy pseudobulb was) there is a huge mass of roots that were rather tightly squished together. I trimmed out what was bad and put in a smaller clear pot, in bark, and I thought I trimmed off most of the strings, it looks like you can still see a couple on this rooty rooty side. Oi.

Hopefully it will keep on keeping on.

WhiteRabbit · #7 07-11-2010, 06:31 PM

If you have a good amount of good roots, I'm sure it will be fine. Rooting hormone optional

I have seen SuperThrive at HD and hardware store in my area if that's something you want to get.

Lady Tottington · #8 07-11-2010, 07:01 PM

I have seen SuperThrive there too, but didn't know what it was and if I needed it

I will get some and try it, I'm sure it wouldn't hurt.

Eyebabe · #9 07-11-2010, 07:43 PM

I get the K-L-N on Rays website.

marydaniellesantos · #10 07-11-2010, 08:08 PM

I think it was retaining too much moisture. Since the pot is quite large and you have sphag moss on top (generally to keep moisture and help with humidity) it is getting too much. So a smaller pot, no moss, and maybe cut down the watering would make your baby very happy.