Phalenopsis dying (mouldy aerial roots) - help!

[geob]

Hi all,

I am baffled with a relatively new Phalenopsis I got given as a present - I have had it about 7 weeks now and all was good at the beginning; It came in one of those double plastic pots, where a little string dips into water and the water gets transferred via that into the soil.

The guy who Owned the shop initially watered it from the top (water went over some of the aerial roots - and we did the same the 2nd time); since then we have just been topping up the water in the large pot however.

The problem is that I get a whiff of mould on the top of the soil and some of the aerial roots look like they have gone mouldy too. The buds have dropped off in the last week and the 4-5 remaining look like they will follow soon. It has also dropped one of the bottom leaves.

Is there anything we can do? Have we made some mistake? I see most of the roots are green, so I don't understand what has gone on. The orchid is inside, temperature steady about 18-20 C and not in an overly sunny spot.

I am including some pictures too to give you an idea...

Thank you!

[Dusty Ol' Man]

From the looks of the pot and the medium, I would repot this as soon as I could into a pot with more drainage. Maybe a little larger and with fresh bark that has been premoistened. The roots in the pot look to be in good shape so the plant should do well. As the exposed roots dry out some the mold should disappear. If it doesn't, I would suspect they have died and could be removed. I'm sure someone else will jump in with an opinion soon.

[estación seca]

The roots in the pot look mostly good. For that reason, and because of the watering method used, I suspect the white material you see on the exposed roots might be mineral deposits, rather than mold. Water is being drawn up from the reservoir and evaporated from the surface. The minerals stay behind, leaving the powdery white coating.

Do you know what the dissolved minerals are in your water? Your water provider should have a water quality report online. When using the wicking method it is best if the water has very low amounts of dissolved minerals.

If you instead watered heavily from above, periodically flushing water through the pot, the mineral buildup would be less likely.

[geob]

Thank you both for your replies - The data for water in my area are as follows -

Calcium: 47 mg/litre
Magnesium: 6 mg/litre
Hardness: 143 mg CaCo3 / litre
NO3: 1.2 / litre
SO4: 25 mg / litre
pH: 7.7

I was more worried since it started to drop all the flowers first (and the ones left look pretty miserable) and also that it dropped one of its leaves.

I previously had another one that showed the same behaviour and after dropping its flowers, the stems started going brown and eventually its core stem suddenly came off the roots (was all black inside, rotten??)

[Roberta]

Dropping flowers is "force of nature". They have a finite lifetime. Also if you just received this plant, the change of environment can cause flowers and buds to drop prematurely, but no harm to the plant.

Your water looks very good - much better than mine... No issues there. What are your temperatures? Phals generally need to stay above 20 deg C, and during the day, warmer is better. Protect from drafts.

[estación seca]

I think the white material is mineral buildup from evaporating water. Wicking will lead to this eventually even if the water is somewhat low in minerals. Just think: All the minerals from all water you have ever put into that container are deposited on the surface, from which the water evaporates. The roots are high points.

As for losing leaves, Phals grown in greenhouses with warmth and high humidity carry more leaves than those grown in most homes, with less heat and lower humidity. It is normal for Phals grown in homes to carry 3-6 leaves, sometimes more. In greenhouses they can carry many more. Roberta's question about your temperatures is also important.

[Mountaineer370]

The plant appears to have abundant healthy roots inside the pot. I can't say from the photo what the whitish stuff on the aerial roots is. Are you sure you're smelling mold and not just an earthy smell from decomposition of the media? In either event, if that were my orchid, I would want to repot it soon. I would put it into a pot with more airflow, like holes or slots on the sides, as well as the bottom. I would pot it in brand-new chunky bark that has been rinsed of any fines (dust). (Bark is my preference, other media types work well for other people.) It does look like it is starting to climb out of the pot, so the next size up would be appropriate.

The roots in the photos are very green, which is fine if you have recently watered. But if they stay that color and don't start to fade slowly to silver, then the roots are not getting enough air. Also, I'm not sure I understand the watering method you are describing, "...topping up the water in the large pot..." Do you mean it has an outer cache pot and you fill that up with water and allow the plant to sit in that? For how long?

Don't worry about the loss of some buds and the lower leaf. Both can be normal when you buy a new plant and it has to adjust to a whole new environment. Speaking of which, I believe your temps of 18C - 20C (about 64F to 68F) are a bit too cool for the liking of most Phals.

[geob]

Thank you all for your replies - I repotted on Sunday as per Dusty Ol' Man and Mountaineer370's suggestion into a bigger pot, in which I had previously made side 'vent' holes as well as drainage holes at the bottom. I also used new bark (advertised specifically for orchids) and I kept the same method for watering (ie. a wick floating in water in a bigger pot underneath - the wick is connected to a small piece of wood that is inside the pot) -

I have attached some new photos - As far as I can see, it has now started yellowing on yet another leaf (it started from the base and is expanding upwards), so I expect it will drop another one.

Guess at the moment it's watch and see - The recommended temperatures for it are different day & night? What is the ideal?

Tks!

[Roberta]

Phals actually like rather uniform temperatures. Not below 19-20 C at night, warmer during the day. (The professionals can mess with night temperatures for a week or two to "time" the blooming cycle, but they will bloom just fine with more even temperatures). They would like 12 hours of light every day... so supplemental light will help facilitate blooming, for growth, just gentle, indirect light.

[Mountaineer370]

Repotting is good, but I have a couple of concerns. It looks like you have one pot that fits rather snugly inside the other, both look to be a hard plastic (or maybe the outer one is glass). The amount of holes you have drilled into the inner pot may not be adequate. I'm still afraid the roots are not going to get enough air flow, especially if it is always kept inside that outer pot.

I see now how you are watering. You are filling up the outer pot and letting it wick up the red string. I can't comment on this as I have never watered that way. I water all of my Phals from above, I don't use cache pots, I just hold the plant in its pot over the sink and use a watering container to pour over the medium until it looks like all the bark chunks got fairly wet. Of course most of the water drains out the bottom holes, but I can still see that the bark chunks and the roots got good and wet. I also always mist any aerial roots, at each and every watering. (My house is dry, especially in the wintertime, when relative humidity can be in the 20s or 30s.) When the roots start to turn silvery and the pot feels light, I water again.

FWIW, I find my Phals do well with temps between about 20C to 23C. That fluctuates with whether it's day or night, summer or winter. Mine also get 12 hours a day of supplemental lighting, a little more in summer.

Lastly, I'm wondering what all the white stuff is in Picture 2?