dendrobium root tips die when they touch medium

[camille1585]

I'm having some problems with my little mini dendrobium 'borneo'. I have saved it from death twice, but it still isn't out of the woods. It bloomed again during the summer and started some new growths/keikis with roots. My concern is that those nice new green tipped roots stop growing as soon as they touch the medium. The green tips turn brown and die. The existing roots of the plant are in sorry shape and don't grow either. Any ideas? This guy keeps me perplex. Maybe Dens don 't like me? I will post pics tonight if you want.

[smweaver]

What kind of medium is the plant growing in? If it's sphagnum moss, it may be too acidic for your particular plant. You might want to either try transplanting it into a new type of potting mix, or perhaps reduce the amount of fertilizer it receives (high doses of fertilizer can also play havoc with the roots of more sensitive orchids).

[Ross]

Mine do this with bark as well. Growing tips are a sign the humidity is good (or so I've heard). Mine are in 90% humidity and do great till they touch the bark.

[camille1585]

I have it potted in bar and I fertilize weakly weekly. I can't remember off the top of my head, but I think it's getting 125ppm N, just like the phals. I thought of fertilzer burn as well, so I've been flushing the pot regularily and it hasn't had fertilizer in nearly a month.
This is frustrating since the roots are gorgeous before they touch the bark!
Any other possible causes you can think of? At this point I think it might be worth it to repot in fresh bark.

[betwixtimes]

Maybe it wants to be an aerial plant. Have you tried mounting it instead of trying to make it terrestrial (planted)

My Dens have finally calmed down from being repotted but I also had some rooting issues---from what I understand Dens can be fickle.

[camille1585]

Originally Posted by betwixtimes

Maybe it wants to be an aerial plant. Have you tried mounting it instead of trying to make it terrestrial (planted)

My Dens have finally calmed down from being repotted but I also had some rooting issues---from what I understand Dens can be fickle.

I didn't think about mounting it. I don 't know where I can find sphag since I'm just arrived in this town, but I know a shop nearby that sells epiweb slabs or 2cm epiweb cubes to use as medium. Do dens do well in epiweb??

[betwixtimes]

I've never grown a mounted orchid, honestly it scares me. In the US, you can get sphag or sheet sphag at the hardware store in bags where they also sell orchid medium like husks, chips etc.

[Ross]

Camille, try this. Try spraying the top surface of your existing medium daily with distilled water only (or RO water). Not "city" water. Just lightly spray the surface several times (depending on your school schedule). I have had some luck bringing some plants into new root growths with this. I suspect the top surface of the medium is too dry for the roots. I'm testing this theory on my tank Dendros to see if this works.

[camille1585]

Originally Posted by Ross

Camille, try this. Try spraying the top surface of your existing medium daily with distilled water only (or RO water). Not "city" water. Just lightly spray the surface several times (depending on your school schedule). I have had some luck bringing some plants into new root growths with this. I suspect the top surface of the medium is too dry for the roots. I'm testing this theory on my tank Dendros to see if this works.

Thanks Ross, I'll try that. This little plant really wants to live. One question, would rainwater work too? I would need to find out what distilled water in called in Dutch!

[Ross]

Originally Posted by camille1585

Thanks Ross, I'll try that. This little plant really wants to live. One question, would rainwater work too? I would need to find out what distilled water in called in Dutch!

Rain water should work just fine. RO or Distilled water is water run through a distillation unit. Hope this helps.