Re: Peat; good or not good

> From: nfrank at nando_net (Neil Frank)
> >
> >The point of using earthworm castings is to provide a high quality,
> >fully composted humus. [snip] It has the (possible) advantage over
> >potting soil in that it does not contain uncomposted organics such as
> >peat. 
> When I said I used peat and vermiculite substrate, I said it was better than
> vermiculite and top soil (and I think the particular top soil was too rich
> with trace elements, so this was not a definitive comparison).

Well, what I think I meant to say was that Neil has been using peat in
substrates and might quibble with a blanket statement that peat
is not a good idea in substrates. Neil, I better let you clarify whatever
you'd like to say about peat in substrates. Since I don't use it at all,
I can't offer any opinions based on my own experiences.

> I am not really very knowledgable about organic matter. What is the
> difference between composted organic matter and peat (partially decomposed
> sphagnum moss), especially after several years under water?

What I understand (also not being an expert) is that humus is the stuff
left in terrestrial surface soil after the microbes have had a good long
time to digest the organic components down to relatively inert forms.
This gives it excellent CEC for binding soluble nutrient cations. 
It also contains compounds which plants can utilize.

The process of composting or organic decay is continual and so you can 
never really say that at a given time it is complete, just more or less
complete. My impression is that with peat, there is still a good opportunity
for a fair amount of further microbial activity which could release nitrates
and various gases. I hope somebody can clarify this a little better.

What exactly is peat and how does it get created? I guess I wasn't being
too accurate in implying that peat is "uncomposted organics". Incompletely
composted organics might be better, eh?

I think the subject of peat has been controversial subject here and as
such there is a (small :-) potential for subjective feelings to get
involved. However, I don't think we should shun the topic altogether.
Personally, I'd be very interested in learning from everybodie's positive
or negative experiences with it. Thanks for the info Neil. BTW from your
own experiences, would you say that certain substrates are tricky??

I think most people would agree with the statement that laterite substrates
are fairly safe (and productive?). I've too little experience to say if
soil substrates are safe but used in moderation, I guess I could say
that they appear to be fairly productive. Laterite appears to have
properties which improve the algae/plant balance (oops, the b word ;-)
Its a bit early, but there seems to be evidence that certain soil
containing substrates also improve the algae situation. I guess it could
be that any substrate which gives the plants an edge over algae would
do that.