Question
Hi,
Two of four of my large Cymbidiums plants have their psuedobulbs changing, and Im not sure if this is good or bad, thought Id ask before it could be too late. Ok the plants leaves are perfect green with little change to them so far, with some small black spots here and there, not so much, it has two or three new growth sprouts that looks great, however the psuedobulbs on the older foliage in the last week have started to shrivel and have truned a pale yellowly brown color.  The only thing I have changed to these plants, is that I removed the very old dark brown psuedobulbs and the tunics off of the remaining ones about four days ago, and I have also started to water them with distilled and/0r rainwater with small amount of fertilizer made for orchids, I have had these for 7 months and just made this water change to them, before, the had softened well water.
    Thanks Breann

Answer
Breann, thanks for raising this concern, I'm going to start addressing this by assuming that you know little about cymbidium growing, so, if I'm wrong, please forgive me.  Cymbidium pseudobulbs that are healthy are firm. It is normal for the old pseudobulbs to turn a dark brown and. also, to shrivel. Even these older pseudobulbs can contribute to new growth in two ways:(1# may give rise to new growth from the very bottom of the pseudobulb; (2) may provide nourishment to new growth as pseudobulbs are storage organs for plant saps containing sugars, hormones, etc..

When you remove old pseudobulbs, you deprive the plant's new growth of needed nourishment and (2) you make the plant vulnerable to infections which may enter through exposed cut tissue. In the normal growth process, as the older pseudobulbs provide its contents to newly growing tissue, it will shrivel some.

The two best reasons to remove old pseudobulbs is, if they are rotten, (to prevent rot from spreading to healthy tissue) and to create a new division for a new plant.  If older pseudobulbs are so soft that you can squeeze the pseudobulbs so they collapse.  This, then, is rot and all such pseudobulbs must be removed and the cut ends of the healthy part of the plant sealed with a powdered fungicide such as sulfur.  If you want to make a division, you will need to remove several interconnected pseudobulbs and pot them up as a group.  Again, you will need to seal the separation wound.  This should only be attempted when the plant is starting its new growth cycle.

When cymbidiums start their new growth they appreciate being fertilized heavily (eg 1 tsp per gallon of water). Use a plant food with a high first number (nitrogen) and, as the new growth matures, switch to a bloom booster (ie more phosphate). Rain water has few dissolved solids. To build strong new tissue, you will need to ensure that your plant food contains Magnesium and/or calcium salts.    If you have a source of hard water, that can be mixed with the soft water to provide the needed magnesium and calcium. Avoid salts of sodium which can be in the ground water near the coast.

Cymbidiums like to be tightly potted so don't need to be repotted more often that every 2-3 years Fall temperatures should be in the 40's at night to help set the buds.  Light levels should be gradually increased during the summer.