Why are my roots dying?

[scy]

Two of my phals recently started dropping leaves. I originally thought it was probably due to too much light as I have them in an east facing window with no sheer curtain. I spotted new root growth in both of them about a month earlier. I even unpotted to reposition them both in their pots, so I was able to confirm the nice, firm, plump, healthy green roots!

My large phal noid started dropping leaves very rapidly, so I finally unpotted it again to see if anything was wrong. I found that there were white moldy (?) spots all over some black roots. Yes, the roots were all dead except for the new root nubs that were growing. I soaked all the roots and PrimeAgra in physan dilution. Now I have it behind a sheer curtain to shield it. On a side note, I have been battling a fungus gnat problem, so I finally got some mosquito dunks and placing them on top of the PrimeAgra and in humidity trays to get rid of these things once and for all. I decided to go through and clean through the green moss(?) in the pots, because it was getting pretty unsightly and smelly.

I just unpotted my phal sogo grape only to find that the same thing is starting to happen with this one too. I did catch it before the roots died. There are 2 bright green ones left but they have dark spots and the ones that have turned black are still firm. I have not cut anything because I'm hoping they are not dead if they are still very firm. I did see some white spots but they don't come off when I rinse them under warm water. I have soaked the roots in physan along with the PrimeAgra and plan on potting them back up.

1st Photo: noid phal
2nd Photo: Phal sogo grape

Why my roots are dying? I can understand the noid phal's roots dying as they were part of the original roots and maybe they didn't take to s/h. However, the other phal's roots were all new roots that grew in after repotting to s/h so they should be tailored to the environment. I would like to do my best to save them. I am going to put them on top of a heating pad and have already watered with kln solution. I'll try to find something large enough to put my large phal in to help raise the humidity. Any ideas on what happened and how I can avoid this in the future? Sorry for the long post. Thanks for your help!

Susan

[King_of_orchid_growing:)]

I don't know too much about S/H, but from what I gather, may I suggest trying a different method of growing the problem plants to see if you can get them to come back.

Same thing applies with orchids potted in S/H as with other potting media in regards to pot size. The pots should be just large enough to fit the roots.

[Orchid126]

Often times young mealy bugs are mistaken for white mold. Are you sure that's what you have and not mealy bugs?

[scy]

Originally Posted by Orchid126

Often times young mealy bugs are mistaken for white mold. Are you sure that's what you have and not mealy bugs?

I don't know for sure. I soaked it in physan solution for 5 minutes and even ran it under luke warm water and tried to gently use my fingers to rub it off. Although now that you mention mealybugs, I wish I had used gloves. Yuck! The spots never moved.

[Zoi2]

This link may help with your fungus gnat problem
Fungus Gnats as Houseplant and Indoor Pests
Your roots should not be rotting in S/H, how often are you watering, flushing, fertilizing, and what kind of water are you using?
Joann

[silken]

You mentioned unsightly and smelly green moss in the pots. I'm assuming prime agra are clay balls and you are using them for SH. So where does the green moss fit in? I'm just trying to figure out how they were potted. the comments about the green smelly moss sounds like too much moisture.

[scy]

Zoi2: I just put mosquito dunks on top of the medium and in the humidity trays. I read the link you provided and it says that the larvae feed on the roots. Could it be that the roots looked that way because of fungus gnat larvae? I am watering when there is only enough water to cover the bottom row of PrimeAgra or just a little less. This equates to about 4 days to a week right now. My watering schedule is alternating between regular tap water and fertilizer solution. At the end of the month, I always just flush out with regular water. I mix a fertilizer solution of 1/8 tsp per 1 qt of tap water. When I water, I pour from the top (avoiding the leaves and crown) until the solution reaches the top layer of PrimeAgra and let it slowly drain out through the 2 bottom holes.

Silken: I made a mistake. It's not moss. I believe it's algae. It's growing on the side of the pots. I don't see it in the middle of the medium. I only pot up with PrimeAgra but after a few weeks, this unsightly green stuff shows up on the side of the pot. When I unpotted to scrub my pots clean, I noticed that it was quite smelly. I also made sure I soaked the PrimeAgra and roots in Physan for a few minutes and rinsed before I potted it up again.

[quiltergal]

Can you show us the S/H pots you are using? I'm wondering if maybe the reservoir is too large, and the pot not tall enough.

[Zoi2]

When you water, how many times do you fill the pot?
How fast is the water draining out of the pot?
I would also like to see a picture of your pot and plant.
Here pretty soon we'll find out what's wrong
Joann

[RosieC]

Another thing with S/H is temperature. The evaporation from the Prime Agra or Lecca can reduce the temperatures lower than the ambient temperature. In colder weather Phal roots especially can have a problem with this (mine did over the winter and started getting black spots that remind me of yours).

With mine I started using a seedling heat mat and that seemed to help. Now with the warmer weather they are doing well without that, but I'm not sure what sorts of temps you have just now and the level of evaporation (thus the amount of cooling) may be different to mine.