White Spots/Buildup on Phal and Vanda Roots

[c123anderson]

Hi everyone. Yes, it's me again. Feeling like someone may need to come and do an intervention with my orchids.

Watering yesterday, I noticed on a few of my phals some uneven white bumps. These didn't appear to be moving, and almost had the appearance of mineral deposits. They're certainly not hairs. I did notice at the crown of one phal some white fuzzy stuff. Of course I panicked and thought the mealybugs were beginning again. I used some isoprophyl alcohol and spot treated the area.

This morning, I noticed similar white spotting on my vanda neofinetias. Again, treating with isoprophyl alcohol and thinking mealys were back.

Concerned plants are potted in sphagnum moss. Roots are declining. I had hoped this was due to the mealybug treatment and roots/plant would rebound, which is generally what's happening.

Do these symptoms (aside from the white fuzzy stuff) sound like mold or deposits and do you have any particular thoughts on how to distinguish?

I don't have any images that are clearly showing what I'm describing. I also want to not dive into a treatment, potentially further damaging plants.

Would cinnamon help in general? Any recommendations for how to use for a mold issue?

Thank you!

[Dimples]

Distinguishing between mineral buildup and mold: buildup is generally hard (minerals = microscopic rocks), most often white or light in color, and can be dusty, flaky, or securely stuck on in large chunky pieces. Mold is more wispy and fuzzy, can sometimes look like little spiderwebs or strands of cotton, and is often white, grey, but can come in lots of colors.

Buildup is mostly indiscriminate and will happen on any surface where evaporation regularly occurs. Mold is most often found on organic material, and specifically on organic material that’s undergoing some stage of decomposition or stays wet/damp for extended periods.

I get a little bit of wispy/strand-y white/grey mold on the top of bark in the pots of my rescue phals when they only have roots up near the top of the pot and I have to water before the bottom has dried out. A spritz with rubbing alcohol now and then keeps it at bay until the roots have colonized the pot and I can let it dry out more often without risking dehydrating the plant.

Buildup doesn’t change appearance when sprayed with alcohol. It looks wet, but nothing else happens. A dab with vinegar will cause a chemical reaction and fizzing.

---------- Post added at 08:50 AM ---------- Previous post was at 08:44 AM ----------

Buildup is common when evaporation is high or mineral levels in the water are high. Mold is common in high humidity or wet and cool conditions. Neither is exclusive to those conditions, but those are the conditions when each one is more likely to occur.

[c123anderson]

Excellent explanation! Thank you!

I took a little alcohol and rubbed it on the white spots, which disappeared. Sounds like it may be a mold.

Any recommendations on how to treat this? I’ll be repotting, of course, but, during repotting, any soaks or treatments recommended?

[Roberta]

Question... how is the air circulation in the growing area? With high humidity, air movement becomes even more critical. Plants could benefit from a small, gentle fan 24/7 if they're not already getting that treatment.

[c123anderson]

They’re actually fairly close to the duct, so the air from our heat moves around them.

[Dimples]

If the mold is only on the surface or exposed parts, I just spritz with alcohol as needed and let anything that can dry out more dry out more. Usually that takes care of the problem but I’m in a warmer and dryer climate than you are.

If you have mold/fungus throughout the pot, something else needs to be addressed. Either the medium is staying too wet for too long, it’s too cold, or something is off and resulting in root decline and/or death, and then the mold flourishes on the dying/dead material in the wet conditions.

---------- Post added at 11:32 AM ---------- Previous post was at 11:30 AM ----------

I don’t have experience treating extensive mold, but cinnamon and hydrogen peroxide are no-nos for roots. Specialty H2O2 products formulated for use on plants are not the same as the stuff sold at the pharmacy. The first is fine, the second is just for removing blood stains from clothing.

[estación seca]

It is normal for wet Phal and Vanda roots to have some white spots when wet.

[c123anderson]

Originally Posted by estación seca

It is normal for wet Phal and Vanda roots to have some white spots when wet.

These actually look like raised, uneven, not symmetrical bumps, like a mineral buildup.

My phals need repotting, so I’ll investigate a little more then. Just wondering if I need to treat.

[Roberta]

I don't think there is anything to treat. Over time, roots just do get some patterns of spots. Nothing that is a problem.

[c123anderson]

I have a couple of photos I'd like to share. Both of these are vanda falcatas. I'm seeing similar chunky white dots on my phals.

The roots were doing better but seemed to decline/become damaged with the insecticide treatment. It's time for a repotting for these plants.