Is this Sunburn?

[DweamGoiL]

I have a Paph Oberhausen Diamant and about a month ago, it got 1 brown spot, but I did notice it was on the leaf that was getting full sunlight. The spot did not grow and the leaf began to look dry like this one:



Now, the leaf looks like it's about to go. It looks like it is the oldest leaf as well so I wasn't sure if it's just dying during its natural course or if I should be worried:



Here are the spots closeup:



What say you?

[Island Girl]

I could be wrong, (b/c I've only had one paph), but it does look like mine did, when it got sunburned. Tho, I'll let the experts chime in.

One thing, maybe it's just me, but it looks like its potted way too deep, I can't even see the crown (In all honesty, I could barely tell it's a paph, it's so deep in sphag)

[DweamGoiL]

Originally Posted by Island Girl

One thing, maybe it's just me, but it looks like its potted way too deep, I can't even see the crown (In all honesty, I could barely tell it's a paph, it's so deep in sphag)

Actually, it's not potted in sphag. It's potted in orchiata and has a sphag topdress. I can go lighter on the sphag though. I was just having a problem with overdrying so I thought the sphag layer on top would help.

[King_of_orchid_growing:)]

It is not sunburn.

You don't need Sphag for a top dressing.

Sphag adds acidity to your potting medium. Paphs usually grow where there are lots of limestone. Limestone has a higher pH than Sphag does.

The parents of this hybrid comes from areas with a high amount of limestone. In fact, one of the parents, Paph sanderianum can be found growing straight out of limestone outcrops and cliffs with some organic material trapped in between the crevices.

http://www.orchidspecies.com/orphotdir/paphiopesand.jpg

You would need to add some dolomite to that potting mix.

Also, check the roots for root damage. Then check to see if the root mass is smaller than the pot size. Choose pot size accordingly.

[DweamGoiL]

Ok, sounds like a plan. I will definitely get rid of the sphag topdress. Will this product below work or should I use a different type?



This is the description:

Espoma 6.75 lb. Organic garden lime is the finest grade of pelletized, dolomite limestone available. It adjusts soil ph so that your plants are able to benefit as much as possible from the nutrients present. These garden lime granules are fast-acting yet maintain a slow release. A single treatment is good for 4 weeks and may be applied throughout the gardening season.

Ok, so while we're on the subject, I also have a Paph spicenarium and am expecting a Paph fairrieanum. Should I also add dolomite to them as well?

[King_of_orchid_growing:)]

The dolomite you have pictured would work. Just add about a small handful of that and it should be good.

The other 2 Paphs are the same thing - wood chips, perlite, and some dolomite.

[DweamGoiL]

Thank you...Thank you!!!

The roots on this plant are pretty plentiful. I had to wind them around the inner edge of the pot to make them all fit. But the dolomite thing makes perfect sense. I did notice that I added the sphag on Sunday and the leaf did get substantially worse now that I think on it.

Again, many thanks!

[King_of_orchid_growing:)]

You're welcome.