Cymbidiums That Have Brown Pseudobulbs.
Brown pseudobulbs can mean a variety of things; one, the media is going bad. Two; you are overwatering, three; you could be under watering, four it has an illness.
I was overwatering. One or two of the cymbidiums would have a couple yellow leaves and start dropping them after each watering. The cymbidiums looked dry and I was watering once every seven days. However, deep down inside, they were damp. I now water every 10 days and that is working better but Idaho is much cooler. If you overwater, put them in a larger pot and let them dry out a bit. Not totally dry but barely damp.
If you repot with new media when the cymbidium is not in bloom, that will be fine. Just remember not to put into a much larger pot, or the cymbidium will work on more roots and not blooms. If your cymbidium is crowded in the old pot, give it about a 1/2 inch more around the pot. This will cause the roots to spread out a little and still bloom later in the year.
There is a known problem called black rot on the roots, University of Minnesota recommends these things: How to Fix Orchid Root Rot
Before Pruning Water Thoroughly. ...
Remove the Orchid From its Pot. ...
Remove Excess Planting Material. ...
Prune Damaged Roots. ...
Spray the Roots with Fungicide (Optional) ...
Repot with Fresh Material. ...
Allow the Orchid to Recover.
Lastly, fertilizing is important too: The American Orchid Society says: “Fertilize at the proper time to help Cymbidiums flower. Use a high nitrogen fertilizer such as (30-10-10) from March until May, a balanced fertilizer such as (20-10-20 / 10-10-10) from June until September, and a blossom booster such as Dyna Grow Bloom (3-12-6) once you see spikes forming in early spring.”
Cymbidiums need bright indirect light. If the leaves are a lovely dark green, they are not getting enough light. I have ‘grow lights’ but here in Idaho May-August we have our summers. Which is great if we don’t have a lot of clouds. Mine go out on the porch but the afternoon sun is too strong so I have to cover them with shades. If we have a lot of clouds in the summer I use grow lights indoors.
