How to use Seaweed Extract to save struggling plants

[drtd]

I have a few sick orchids that are struggling to put on new roots and I was thinking about using seaweed extract to help things along. I just have a couple of questions about the application process.

1) Do I apply it to the media, or directly to the existing roots (of which there are very few)?

2) How often should I apply and at what strength?

3) Should I discontinue when I observe new root growth, or continue for a set period of time to ensure success?

Any input in this matter would be helpful as I have never used seaweed extract before. The plants that I am trying to save are a NoID Phal that has been struggling to put on new roots for a few months now, and a division of Ornithophora radicans (formarly Sygmatostalix radicans) that has been struggling a little since being divided from my mother plant a few months ago.

-Danny