Vandas not producing roots

[Sahil]

Hi, im new here , trying to get some advice on growing vandas I have a collection of a few vandecous orchids.
■Grown in 40Watt Full spectrum Led lights, hanged right on top of the vandas. Watering is done thoroughly once every morning .
■Temperatures are usually around 30° Celsius
■Placed in big clear plastic pots, the pots have a layer of pine bark at the bottom , and the roots of the vandas are right on top of the bark , so as the bark when wet provides humidity and at the same time roots get the breeze/air circulation ...so no suffocating the roots

All the rhynchostylis , renathera and their hybrids are doing very well and have new roots and leaf tip emerging under my care , they love the led more than natural sunlight... But the typical vanda types have not produced new roots or root tips or branching in the past 3 months, only growing leaves every now and then ....examples- kulwadee fragrance, pachara delight, varult leopard , hollutiana etc

I have tried spraying kelp max , provide good watering and light but still they refuse to put out new roots or branch out from existing roots , The foliage looks healthy and apple green in color , roots turn green on watering but still im not seeing progress in root growth...
Any suggestionsor advice on how to make them grow roots?

[Ray]

As you have Kelpak (formerly relabeled as KelpMax), rather than spraying the plants, try immersing them for about an hour in a 1% solution.

That, plus very warm and humid, should do the trick.