Niveums silver leaf, nutrient deficiency or?

[IvoPhal]

I have 2 pots 12 cm with 3 niveums. They are potted in bark, perlite and quarts sand. I used in thei culture since September kelpak and akerne feet, calamag, oyster shells sand and some seaweed. All are derived from 1 pot when I bought it.
The 1 one is in good shape planted alone(see pics) the other one is in bud with 2 yellow leaves ( that’s my concern) and the other one is not growing.
Why they react so differently? They are treated the same way, light, temp at the windowsill? Is there some nutrient deficiency or I have to see roots ….

 

[big923cattleya]

Are those mealybugs down in the growth with the bud? It sure looks like it but from your images I can not be sure.
This group of orchids, the Brachypetalums are fairly slow growers. They live in the leaf litter one top of limestone outcroppings. They never really like to dry out and mine do not seem to enjoy being too wet either. Niveum, concolor, godefroyae, bellatulum, leucochilum, etc. all feature dark green leaves with silver markings or tessellations.
They are small plants, I would be careful about applying too much fertilizer. I my experience under lights, they prefer subdued light and both concolor and bellatulum are the easiest for me to grow.

 

[IvoPhal]

No, it’s not mealy bugs, oysters shell sand but a messy application
Actually the question is that one plant potted in 2 pots, the same media , fertiliser msu/akerne 100 N ppm weekly is growing differently.
1. Is growing with strong leaves
2. Is blooming but the the leaves are yellowing
3. Plant it’s not growing

 

[Stone]

The first leaves yellowing when the plant is coming into flower is usually potassium and/or nitrogen being removed to enable flowering to continue if these elements are deficient in those leaves. Given that niveum normally flowers in the spring, it should be able to flower without any fertilizer being applied over winter and still hold the old leaves. But note that it must have good roots during the previous growing season to be able to accumulate these elements well. Niveum is a completely tropical plant and prefers minimum overnight temperatures no lower than 18C during rest or at the very least 15C if kept almost completely dry. When the leaves are yellowing and the plant is blooming it will most certainly not do anything for months after blooming is over as it will completely exhausted. They do not like repotting either.

 

[IvoPhal]

Thank you, I appreciate your input. I understand completely what you mean.

 

[Tom-DE]

For windowsill growers--If you feed your plants, even if just only once a month, nutrient deficiency is uncommon IMO. This time of the year(winter), most of the Brachypetalum will not do much anyway. Also, the roots are sensitive to salt accumulation. The excessive yellow leaves or immature dying always trace back to the salt problem at the roots for this group of Paph. I will check if the mix is still fresh with good drainage, and also check the root condition. Flush the pot often...

 

[BrucherT]

When were these plants last repotted? To me, the mix is looking old. I disagree about these not liking to be repotted. I find the respond to repotting like all Paphiopedilum and that old, rotting/breaking-down mix is a problem. It’s self-fulfilling, too, that if you wait too long to repot, they will already be suffering and then of course they’ll struggle initially when they do get repotted.

 

[Tom-DE]

but how often is it? I don't think it is necessary to repot Paphs often either. You may repot seedlings more often but for mature plants, It is not necessary, unless you have bad water or bad culture practice.
I repot my mature plants every 3-4 years, in generral.