Yellowing leaves on P. bellatulum

[Fredmax]

Hi, I was hoping to get some advice on what may be affecting my P bellatulum (or godefroyae the tag has faded) I grow this with my other slippers including hirsutissimum, appletonianum, micranthum, delenatii, concolor and others which are doing fine but this yellowing started spreading and looks like the worst scenario is inevitable, I've brought it indoors thinking it was too cold or too high humidity which has only made it worse.

Could it be underwatering? Should I repot it into sphagnum or try to relocate to a warmer spot or in a terrarium? It's currently potted in 6inch bark with 10% crushed seashell, watered weekly, fertilised monthly, 90% humidity, heavy shade, 18c-11c daily temperatures and not seeming happy.

 

[Ray]

When you feed monthly, what formula and concentration do you use?

Personally, I think very frequent/very dilute feedings are better and safer than infrequent, concentrated feeding.

All of my plants are doing quite well with a weekly, 100 ppm N feeding using K-Lite (12-1-1-10Ca-3Mg). That's about 1/2 teaspoon/gallon and equates to a TDS of 770 ppm contributed by the fertilizer. If you were to try to duplicate that with a single, monthly feeding, that would be 2 teaspoons/gal and 3080 ppm TDS, which I would think is potentially damaging to the roots.

 

[GuRu]

In my eyes there shouldn't be a feeding problem. I would think of other things.
Have you checked the base of the leaves ? If the plant sits too deep there is often rot or an infection e.g. of Erwinia which makes the base of the leaves rot and they are strangled from the center of the plant and turn yellow and die eventually. Another option .... have you checked the roots ? Are they healthy or rotted ?

 

[Paphman910]

Check the health of the roots!

It should be grown in warm to intermediate temperature and medium light.

I think sphagnum moss will be too wet as the roots like to approach dryness by the evening.

 

[BrucherT]

When you feed monthly, what formula and concentration do you use?

Personally, I think very frequent/very dilute feedings are better and safer than infrequent, concentrated feeding.

All of my plants are doing quite well with a weekly, 100 ppm N feeding using K-Lite (12-1-1-10Ca-3Mg). That's about 1/2 teaspoon/gallon and equates to a TDS of 770 ppm contributed by the fertilizer. If you were to try to duplicate that with a single, monthly feeding, that would be 2 teaspoons/gal and 3080 ppm TDS, which I would think is potentially damaging to the roots.

Ray I'm surprised reading this. I have been using only 1/4 tsp per gallon of K-Lite. Are you really using half a teaspoon or is that a typo? Thanks.

 

[Ray]

Ray I'm surprised reading this. I have been using only 1/4 tsp per gallon of K-Lite. Are you really using half a teaspoon or is that a typo? Thanks.

For 100 ppm N, K-Lite requires 0.77 g/L, or 3.785 x 0.77 = 2.9g/gal. For most dry powders, a teaspoon is about 5 grams, so 1/2 it is.

In reality, I make up a concentrate of 92.8g/half gallon, then dispense 2 fluid ounces of that per gallon to give me the 100 ppm N.

I use that concentration for feeding once a week and I flood them 2-3 more times a week with plain water. If I fed twice a week, I’d use half that.

 

[SuperPaph]

I agree with GuRu, to check the base of the leaves, but loocking not only for Erwinia, but Mealy affects leaves in a similar way.

 

[Fredmax]

Thank you for the advice, I should've checked myself but the plant roots had mostly rotten and was down to one strong root, while unpotting I noticed 7-8 mealy bugs under one leaf too. I'll try and get a current pic of the root, not too sure on next steps but I've sprayed the roots with Hydrogen peroxide and will let it air out for 24 hours before potting in fresh orchiata and hoping.

 

[Ray]

No drug store hydrogen peroxide on roots!!!

“Drug store” H2O2 is 3% concentration and is barely stabilized with stannous chloride, so the energy release is sudden and violent - and sufficient to damage root hairs.

If you want a peroxide-based disinfectant, get some Oxidate 2.0. It is stabilized with peroxyacetic acid for a much more controlled and mild decomposition, with application concentrations of 0.27% or lower, staying chemically active until it is dry.

 

[PeteKurt]

How did you go @Fredmax? I'm having a similar problem with one of my plants and hoping I can save the plant.