I is actually good for them but I don't cut mine either. I love long roots on my vandas. I sure do miss you Don:(

I need some roots because I want to try germinating some seeds the symbiotic way.

Can someone help me?

To me, I have always interpreted "root disturbance" in the context of moving Vandas between mounts or pots, OR with regard to the notion of causing true abuse to healthy aerial roots. OK, I admit, the machete business does, to me, sound like abuse... I also admit to having had, early on, a period of taking near-fetishistic pains to avoid "disturbing" aerial roots.

On the other hand: These days, I frequently dunk vandas into buckets a fraction of the depth of the root length... and have on occasion pulled the plants loose from some entanglement, resulting in aerial roots breaking off. None of this kind of activity seems to cause any impediment to growth or flowering.

On the other other hand, I've taken to heart the idea that, those roots which are affixing the plant onto something should NOT be disturbed - soaked or pried loose, re-arranged, cut, braided, or otherwise injured. So when I re-pot or re-mount a Vanda, I just find a bigger pot or mounting object than the previous one, and tie the whole thing, old mount/pot and all, right onto or into the new mount/pot. This gives the plant more substrate to grow onto, without disturbing any of those roots which were already supporting the plant directly on the old substrate.

Works for me.

Machete or sterilized blade, cutting vanda roots actually stimulates their branching, thereby increasing root mass. Sounds awful, but since I can't raise the roof on my greenhouse that's 11 ft tall at its highest. I either have to dig a hole or trim the roots on one plant whose stem is 4 1/2 ft tall with 6 ft + roots.

Don't know what I'll do when the roots branch so densely that I can't get the plant out the door :)

Cneos "dig a hole or raise the roof" LOL. I love those big monsters though. I wish I had acres and acres of land to fill with trees and put vandas all over them. Well some others too.

Ditto Swamper!

Don,
There are two rules of thumb that go with regarding long roots on my vandaceous plants.

One is to loop the roots up so that they don't hang too low. I've included a few pis. The first two are my V. sanderiana currently in bloom, roots and bloom spike. The second two are my V. lamellata, roots and spiking top with 17 spikes. :D

The other is to actually trim them; however the trimming needs to be done near the beginning of the more active growing season, which for me is mid to late spring. At this time, you can (I do without problems) take off as much as 1/2 to 2/3 of the root length, being sure to spray afterward with a fungicide. As pointed out by others, this can be beneficial to the plant, causing branching and additional new root growth to occur. There are a couple of commercial interests in Homestead that do this every year as a basic practice in their shade houses.

I hope this helps, David