mold misadventures.

[therainytype]

i have two phals planted in sphag. that seem to have a bit of a mold problem.
it tends to form on parts of the roots a few days after i water, and i'm not really sure how to get rid of it.

when it first started to form, i tried removing the bits of moldy sphag. from the pot and gently swabbing the mold off of the roots with a q-tip. this seemed to work initially, as a week or two went by and i didn't see any more of it. however, it's come back here recently.

i don't think it's a case of overwatering since i use the bamboo skewers and water only once every ten days or so (if even that). i have another phal in sphag. that i water along with the other ones and it seems to be just fine. the two phals that i'm concerned about seem fairly healthy otherwise, as they've been showing new growth and the leaves look nice and green.

i'm thinking it might either be the sphag. itself or my growing conditions. the two phals are in plastic pots and grow about six feet away from an eastern window that receives lots of bright morning light. i try and keep my ceiling fan on to keep up the air circulation, though i'm worried it might just make the room cooler and encourage the mold to grow.

i've heard that pouring hydrogen peroxide over the roots is one possible solution? i'm thinking i might just need to repot though, as i haven't yet since i bought them. suggestions?

[Cynthia, Prescott, AZ]

I would not repot for this reason. The hydrogen peroxide sounds reasonable, tho I would put a fresh batch in a spray bottle every time it is used. I have started spraying the tops of some of my pots with a Physan 20 solution. What seems to be most of my problem is not mold, but algae. Physan sould work on both. Just don't use the Physan solution like it is a watering substitute. At some point, it may not be good for the plants, but an occasional use should be OK. Cynthia, Prescott, AZ

[jerrymeola]

Many nurseries think that Physan (which is a contact algaecide) is not any better then Hydrogen peroxide. They will work the same. I know one nursery that uses Physan weekly in the greenhouse. For him it stops all algae and greatly slows the decomposition of bark in his mixes. Either should work fine for your problem.

Cynthia's suggestion of a spray bottom is the easiest application.

Keep in mind that Hydrogen peroxide breaks down when exposed to air and has a limited shelf life, fortunately it is cheap.

[Tmai]

Interesting thread! I have been lurking for a while and have learned quite a bit from this forum.
I recently received a bareroot vanda from a mail order nursery. The plant (vanda ascocenda Suksamran Beauty) arrived with black spots along the edges of some of the leaves and a green algae (?) growing on some of the roots. The plant has a nice wad of viable roots and has had one leaf turn yellow (a lower leaf). The black spots do not appear to be spreading. Have kept it in bright light, no direct sun, and have sprayed it with neem and used superthrive/fert separately. Do I need to be concerned about the green stuff on the roots (maybe use the hydrogen peroxide or physan?) or the black spots on the leaves? Thanks for your help!
Tmai

[Cynthia, Prescott, AZ]

The black spots were probably caused by misting or watering late in the day so the plant was still wet when the temp started to fall, or the plant was allowed to get to cold. No fix for this, as those leaves will always have those spots. But, keep the plant warm, and don't water/mist late in the day and you won't get any more of them.

Algae or mold should be addressed by an occasional spraying of Physan 20, or, as others have suggested, hydrogen peroxide used fresh out of the manufacturers bottle each time you spray with it.

Your first picture will not open up for viewing. Your second picture does not look green enough to start worrying yet about spraying. Cynthia, Prescott, AZ

[Tess]

Can anyone tell me the peroxide formula for mold?
I re-potted a phal from spag to bark and everywhere there was a little tiny bit of spag left in pot, there was mold.
Thanks

[Cynthia, Prescott, AZ]

I believe it was recommended to use it straight from the manufactuters bottle. Cynthia

[Tess]

Cynthia,
Should I just pour it through the bark?
Thanks, Tess

[Cynthia, Prescott, AZ]

That is my understanding. Cynthia

[Aniko]

Hi, Tess & Rainytype!
Did you try the peroxide formula for mold?
Please, let me know how it worked for you, and where you bought the solution (pharmacy? garden center?)
( I've just discovered mold on some of the sticks used for controlling the moisture.)
I'm looking forward to your answers.Aniko.

[mayres]

3% hydrogen peroxide is extremely common and used for a wide range of applications - and can be found at just about any/all pharmacy locations - in grocery stores, walgreens, rite aid - as noted - very inexpensive. Solutions that are purchased for lab/scientific use are usually 10X as concentrated (will burn on contact and should be used with gloves and safety glasses) and would have to be diluted.

[Cynthia, Prescott, AZ]

The skewer is getting mold because the mold/fungus likes the wood in the skewer. I don't think you need to treat the entire pot of mix. My solution for the black fungi that starts to discolor the stick is to soak it in a 10% or higher bleach solution until it is back to normal color, then rinse lightly and return to the pot. I don't think the peroxide will change the color back to normal. 10% bleach is a standard for disinfecting tools to prevent virus transmission. Cynthia

[Aniko]

I'm afraid, a have to treat all the mixture.I searched the medium deep in the pot and I've seen developing some blue-green mold right on the bark.This is the case of 2 of my new plants.This new, bluish fungus appeared in 3 days on the skewer.

I've seen some black coloration on the skewer at an older plant, which has developed in weeks. That was, I think, the case mentioned by Cyinthia.
(One more benefit of using a skewer! informs you about what is happening in the depth of the medium: apparition of fungus, insects.)

[Cynthia, Prescott, AZ]

Two possibilities I can think of. If you are fertilizing a great deal, this fungus may be living on the fertilizer. A good flushing to get rid of the old fetilizer and to prevent build up may help. Also, these plants may be potted in a bark that is of lesser quality than a good fir bark. I think that an Orchid Bark is usually one that has been steamed to kill fungi and mold. The peroxide may take care of it, or repotting may be needed, but for the sympodials, like Catts, Dens and Oncidiums, repotting should only be done when the new growth is just starting a flush of new roots, Phalaenosis can be repotted any time since they are less seasonal, and have roots less likely to be broken if you are careful removing the old bark. Paphiopedilums have tough roots and are repotted any time. Cynthia

[Aniko]

I'm going to consider everything you said, then proceed.
Thanks for the great help!
Aniko.