Hello to everyone! Here is my Grammatophyllum, very sad one. So the short story - i got in back in may, big division (how it was advertised). Repoted it right away from bark to a mixture of lava rocks and sphagnum and everything was fine for three months and than as soon as new growths matured something went wrong. Leaves all turned brown (first ones were on new growths in the middle) and died off. Today unpoted it, cleaned all roots (some looked dry, other looked rotted, probably the oldest one) and here is what i have left with. A lot of new growths (one of the new one just fell off), no new roots and it feels like roots are growing couple of inches and then stop. So question is - how to save? I have all same issues with grammatophyllum, grammatocymbidium, cymbidiums and most of oncidiums. But oncidiums are in pure sphagnum now and indoor. So looking for any help.
To me, that sounds like a lot of repotting and growing media changes in a very short time.
I suggest leaving it bare root until you have researched the most appropriate growing medium. Spray the roots with good clean water once daily.
Research the growing medium you want to use. Look here on Orchidboard, but also consider Googling "Baker culture sheets" for orchids. The small fee is worth it. See what other people grow similar plants in.
When you find what you think is the best medium, repot. DON'T bury those new growths. Make sure not to over-water (better to water too little than too much). Afterwards, resolve to make no more media changes or repotting for a year.
The mix you show is far too dry, made more for hydroponics growing. Find another mix which holds more water. Cymbidiums and oncidiums will require different size water retaining media. Do your research before repotting again.