sorry about misreading the H2O2 quote.........indeed you said oxygen boost and not nitrogen boost.

S/H stands for semi hydroponics.........go back to semi-hydroponic culture and read the sticky posts to learn more,,,,,,,,or visit firstrays.com

Semi-hydro. It's a method of growing without the traditional medium and uses expanded clay pellets--no bark,no coconut anything, and no sphagnum (no mess!!) For a detailed explanation see Ray Barkalow's web site at Firstrays.com...:waving

here's another good approach to s/h:

Why I use semi-hydroponics - Orchid Board

Have you considered that the spots on the roots may be due to algae, and not the actual root itself. I have about 30 plants in s/h now, and in most cases the roots find their way to the edge of the container. They seem to like it there. I have not seen any roots die from growing like this.

Tyler

that root is now dead and black. It was not a case of algae.

Algae
 

I have experimented with S/H this year and have noticed green algae on the inside of the containers. I have added some fungicide but it doesn't go away. Doesn't seem to be doing anything bad, but should I worry?

Algae is an aesthetic nuisance only.

Once it has grown, it cannot be removed in-situ. Killing it in place results in a lot of dead crud in the pot, which probably isn't the best for the plants.

Prevention is the key: either prevent the light from getting inside the pot (opaque pot or pot cover), or periodically drench with Physan or bleach to keep it at bay.

Check out this link for all you need to know.
Orchid Growing Supplies Semi-hydroponics Hydroponics Orchid Books PrimeAgra

So it's happening again. Yet another root that grew to reach the container side is turning brown, where water is kept between the root tip and plastic.

I DON'T KNOW WHAT TO DO!!

That is just odd. Obviously something is stressing the root. Could it be something about the pot itself?

I would like to clarify a slight misstatement of something I supposedly said:
It is my understanding that the typical scenario is more like this:

1. Some stress is applied. It can be suffocation, poisoning, even temperature extremes. (Obviously any one of those can be instantly deadly if extreme enough, but that's not typically the case.)
2. In response, the plant produces phenols in the root zone to "chase away" the stressing agent. This is common in plants, primarily to reduce competition for nutrients or light. (For example, one of the reasons charcoal is added to tissue culture agar is to absorb it, preventing the seedlings from killing each other.)
3. Unfortunately, those phenols are toxic to the producing plant as well, so unless the stress is relieved, they will continue to build up, killing the roots of the plant.
4. Once the tissue is dead, it will begin to rot.

If I'm not mistaken, those phenolic compounds are typically brown in color, so browning of roots can be an indicator that something is stressing them, but 1) it may be too late at that point, and 2) tannins from bark can tint them brown too.