If you've been following our posts, you'll see that we've gotten a few beautiful peloric dendrobiums from the market. Although the plants seemed healthy and were in full bloom when we got it, an inspection of the roots after purchase told a different story.
While the plants were at some point growing extremely well, as we can see from the mass of roots, most of them are actually dead, either soggy/mushy, or dry and hollow, probably a result of overwatering. Sadly this is quite a common occurrence with store bought orchids, as the storekeepers are usually not the growers and may not know how to give them the correct care.
Only a few small healthy roots can be seen, the ones with the green root tips. That indicates the root is still alive and growing, and if you were to touch them they would feel firm and not spongy.
A good thing about these Dendrobiums however, is that they are extremely hardy. The canes are still firm although slightly shrivelled, and if given treatment they should recover in a few months. All you need are a pair of scissors and tweezers.
First, soak the roots of the media in water for 5-10 minutes to soften them and loosen the old growing media. Then sterilise all cutting tools over a flame, or with bleach. That will prevent the spread of bacteria, fungi or viruses. Using the tweezers, carefully remove as much of the old material as possible. The tweezers will also come in handy in testing which roots are still alive and those which are already dead. This plant was grown in a huge chunk of coconut husk, and that easily holds too much water at the roots causing them to rot.
Dead roots are hollow and dry, or mushy and soggy. The velamen also detaches easily from them, and they may appear white, yellowish or black (which indicates some kind of rot). Such roots should be trimmed off with the scissors.
And here it is with most of the media and dead roots removed. We've left some there because there are new roots growing and we didn't want to damage those new root tips. This plant is now ready to be repotted in new growing media. We recommend charcoal or leca as these are very porous and promote healthy root growth. As an added precaution, soak the roots in hydrogen peroxide or a fungicide/bactericide bath for about 10 minutes prior to planting.