Few roots rotting, what to do?

[supersheep]

I've definitely got the Orchid bug! But I seem to keep on killing them! I'm hoping you can help with yet another ailing orchid!

I got one a fortnight ago and I repotted it the day I got it in fresh orchid compost. The roots looked very green and healthy.

Anyway, the last few days I've seen that a few of the roots near the base of the plastic pot are going a bit mouldy and black.

Is there anything I can do to help with this? The flowers are looking very nice still, but two of the small leaves near the base went yellow recently. The other 3 leaves look very big and green and healthy, as do the other roots.

So I think the orchid is still healthy enough, but I'm worried about the couple of roots that look like they're rotting...

[SlipperGirl]

Could you post some pics

my guess is you will just have to cut the bad roots off

[Wild Orchid]

In my experience, most Phals sulk after repotting. Go very gentle of watering, let the roots dry well before you water again and there's no condensation on the walls. I hope the medium you used is not packed too tight between the roots as they need to breath. It might take up to a month or longer for a Phal to get adjusted and start growing new roots.
If you're seeing some signs of plant weakening like limp leaves, I'd cut off the spike and put it in a vase (it would last just as long), allowing Phal to gather its strength.

I've recently discovered that adding some light helps the recovery and accomodation process. I don't mean a blasting sun but just a slightly brighter spot. I've started noticing some progress with recovering Phals when I've placed them under the daylight type bulb.

As for a few rotting roots, in some previous discussions more experienced members advised to let it be. You could also briefly dunk the pot into Physan 20 to eliminate the bacteria.
Of course, if you observe the extensive root rot, then another repotting might be due.

Hope this helps somewhat.

Lilia

[supersheep]

Thanks for the help. I can't really post any pictures, because the mould on the roots is not that easy to see even with the naked eye.

I'd have to repot to cut the bad roots off, so as you suggest, I'll let it be for now. It's only on the bottom of 2 roots so far, and there's lots of green ones. I can see it quite easily and hopefully it's not spread to any roots I can't see further in the pot.

I tried to keep the potting medium as light as I could when I repotted, so hopefully it won't be too dense. I do wonder though if the bark compost I got wasn't that good... Another orchid I potted in stuff from the same bag has gone mouldy...

I read that hydrogen peroxide can be used for mould, but I'm not sure how that would work... Would I dilute some in water and leave it to stand in it for a bit? Would it damage the healthy roots? I don't think I can get Physan 20 easily where I live, but I got some 6% hyrdogen peroxide from the chemists today.

I'll definitely keep an eye on the leaves and cut off the flower spike as you suggest if they go limp. And I'll try and give it more light - maybe move it as close as I can to the window in the day (it'll be sat on my bed, so I can't leave it there all the time! LOL!)

[WhiteRabbit]

You can use 3% H2O2, I guess if you have 6% you could dilute it by half.

[supersheep]

Originally Posted by WhiteRabbit

You can use 3% H2O2, I guess if you have 6% you could dilute it by half.

Ok, I'll try that. How long do you reckon I should soak it in the H2O2 for?

Thanks!

[Stray59]

Can't speak to the soaking of the plant in H2O2, but overall I think the plant is just in transplant shock. If the bottom two leaves were small, they were probably just aging out anyway and the transplanting just did them in quicker - also, if you did not remove the dead or dying roots when you repotted, or if you damaged a couple of the bottom roots, you may just have a few that are starting to deteriorate. Again, just be careful with keeping it too wet - also a small fan nearby can move enough air to cut down on mold and mildew problems. It's really a wait-and-see issue - any more loss of leaves could signal the need to intervene.
Hope this helps
Steve

[judylscott]

Rotten roots and yellow leaves mean you are over-watering. The potting mix should get dry between waterings.

[supersheep]

Thanks for the help guys! I'll leave it as it is for now, but keep a good eye on it. Hopefully it won't get any worse.

And I'm trying very, very hard to not overwater! I'm waiting until the roots near the bottom of the pot have gone silvery in colour before watering.

[Ray]

I will have to disagree with Judy's assessment. Most of the orchids we grow originate in areas of the world where they stay constantly wet, so the need to dry between waterings is incorrect.

If you use a poor potting medium for your growing conditions, and it becomes saturated when just watered, including water being held in-between the particles, then you can suffocate the roots, and that's what kills them.

However, I think that you're merely seeing the "changing of the guard" as it were...

As roots grow, they "tailor" themselves on a cellular level to the environment into which they are growing. Once they have grown, they cannot change. Move healthy roots from one environment into another (as we do when we repot), and those roots may not function so well. As new roots grow, they will be perfect for the new environment, and we expect the older ones to fade away. That is why "right when new roots are emerging" is the ideal time to repot.

Kep your plant otherwise healthy, and the "root transition" should go smoothly.