No ID dendrobium

[LFC25]

This is a no ID dendrobium just finished flowering. I waited till new roots and new shoot growth then I repotted it to S/H.

Few questions here:

1. The new roots (next to the new shoot) were green in color before repotted. After repotted, it became brownish and also look soft. Are the new roots already dead?



2. These are old roots. Are they also dead?



3. These are old stems and have been this way for the past 3 months. Are they also dead or they will grow again?



Sorry for the many questions as this is the first dendrobium I got.

[Bulbopedilum]

===Advice from a guy who rarely repots and is not too experienced===

In my opinion you don't really need to worry too much about stuff being dead and not dead.

Are the roots in pic 1 mushy? Try slightly pinching it and sliding it. If a "sheath" comes off that reveals a white string, the root is dead, but I don't do anything with dead roots. Sometimes I cut them off but most times I don't care.

On the third pic, let the pseudobulbs (Are they pseudobulbs?) be. They can still be use by the plant for storage and photosynthesis. Don't remove these.

I'm not sure about pic 2.

The plant itself looks good. The shoot will make new roots.

[LFC25]

Saka, sad to tell that the new roots are already dead. The 'sheath' came off easily when I tried to pinch the roots. I always thought re-potting when there is new growth will not cause new roots to become dead

[rbarata]

As far as I know, when you change from one type of culture into another, the roots already born will die.
I think, as you have a new growth, and if it continue to grow then everything must be fine. Also, from that new growth it's probable that new roots will grow.

P.S. - I think I see the tip of a new root at the base of the new growth.

[Optimist]

Orchid roots are an interesting topic. They are young and new on the new growths, and then they are in various stages of senescence (a word for "aging") and then, when the old back bulb is used up, they die off all together.

So, look at your plant. Do you have any new root tips under the youngest leads (a lead is a new growth)?

If you do, then all is not lost. The old roots were going to die anyway. The new medium may have helped it happen faster, but your roots will get used to the new situation. Dendrobiums are very thirsty during their growing period. They also need a bit more fertilizer than other orchids.

People think that orchids feed from their roots, at the time that they are getting watered. This is not the case. They first transfer and store the raw materials they need to live (elements, minerals) into sugar which they store in their pseudobulbs. It is the same way that people do not actually eat their food, they store the molecules of the food they eat in their fat, and they eat the fat many days or weeks later).

If an orchid has a complete pseudobulb, then that pseudobulb does not need roots any longer. It will remain alive, but it is a living food storage for the growing plant, which is the new plant. The new plant has the roots.

[LFC25]

Originally Posted by rbarata

As far as I know, when you change from one type of culture into another, the roots already born will die.
I think, as you have a new growth, and if it continue to grow then everything must be fine. Also, from that new growth it's probable that new roots will grow.

P.S. - I think I see the tip of a new root at the base of the new growth.

So we shouldn't change the type of medium

[rbarata]

Originally Posted by LFC25

So we shouldn't change the type of medium

Yes, you can. Right before new roots start to grow (or right at the beginning) that's the best time to do it. This way new roots will adapt to new medium because they don't know any other than the one on which they are growing.

[LFC25]

The new shoot has grown taller since I last posted on the 17th. One new root also grew out.

Should I really ignore all the dead roots inside the pot? I'm thinking of un-potting it and remove all the dead roots. Do you think it is wise to do it? Will the new roots be damaged easily?

[rbarata]

I think the new roots have higher probability to get damaged if you mess with them (trim dead roots, repot, etc).
So, I would leave it as it is.

[LFC25]

Originally Posted by rbarata

I think the new roots have higher probability to get damaged if you mess with them (trim dead roots, repot, etc).
So, I would leave it as it is.

Thanks for that advice. However, will the dead roots cause have any ill effects on the plant if I leave them too long inside the pot?