living plants creating soil

I was wondering ..pretty much everything I have heard about plants "making" soil involves composting. Although some plants bring minerals and so forth up from the subsoils, to actually create soil generally seems to involve something dead ..leaves, roots etc being turned into soil. However...

I have a couple of spider plants in the house that tend to get exuberant and need to be trimmed from time to time. The last time I ran out of soil to put one of the offshoots into so simply put it in water (I hate killing things that are trying earnestly to live  ) and sort of forgot about it, just adding water to it as I did to the other offshoots.   Today I actually looked to see which was who..couldn't tell as they are all  healthy..and I couldn't believe it.  The one that had had only water has a big ball of SOIL around its roots!.  The plant must have taken minerals from the water and air and turned it into soil somehow. They are one of the plants known to take contaminants out of the air but this seems remarkable to me.

Are there other plants...ones that will live outside in a cold climate ..which will do this? Something that will live rambunctiously AND "grow" soil seems to me to be worth looking into. The other offshoots..the ones that had soil all along..don't seem to have produced any extra soil, though I didn't  measure anything when I potted them so can't be sure of that.  All quite astonishing. 

There probably are similar plants that do such a thing, however, this sparks a tangent.

Watching Lawton's "Soils" we see him creating compost that is inoculated with a variety of biological substances: cow, pig, human, duck, goat and chicken crap, a dead animal, some comfrey and green grass in a carbon bed of straw and wood chips. This mixture allows the development of beneficial bacteria and fungus.

Watching "Terra Preta" we see an ancient amalgam of biological substances including crap, charcoal, bone, and so on with a population of bacteria and fungus that actually grows the Terra Preta substance, effectively converting normal soil into this richer concentration of biological action.

It seems that by creating this sort compost we are creating soil seed, taking the slower natural process of decomposition and speeding it up almost exponentially. Turning normal soil into super soil.

So, to answer your question, yeah, probably any plant that has water roots like that (mint, willow to name a few) will take minerals out of the water and create "soil", however composting does a much more effective job.

To further the point, it is not the base of minerals that creates excellent soil, it is the addition of a diverse (on every scale) biological life that facilitates accelerated biological growth.

Thanks for your response but  I think you missed the point I was trying to make. I am not suggesting that this is in any way "better" than composting. I was simply astonished that the plant had made soil without having to have parts of it die and compost. It is not normally a plant grown in water but being an almost indestructible and useful  indoor plant it seems to accommodate whatever conditions it finds itself in..lots of light or hardly any, lots of water or hardly any. It will manage without watering for an amazing amount of time, so I'm not sure it would fall into the same category as willow for example. Don't even water lilies require planting in soil, under the water?

I haven't tested it..maybe I will at some point..to see just what is in this "soil" but right now it looks like humus..dark brown and cradling the roots. And..  although bacteria and microbial life etc are indeed essential for healthy soil, nothing will grow without the right mineral components as well. Sometimes only minute quantities ..boron comes to mind.  Thus the very wealthy fertilizer manufacturers. I am not familiar with anyone who is presently packaging up soil microflora for increasing soil productivity..perhaps there is a business opportunity for someone!

In any case I wasn't  suggesting that this soil is better than that made of compost (in my climate it is certainly faster than making compost  in the wintertime! ). To me it is a phenomenon  not seen before and I would like to know - not guess-  if other plants share this ability, and if so  which ones. 

The tiny "root hairs" of plants allow soil creation during a plant's lifetime, since they grow out from the root briefly and then die once they harvest the nutrients from their spot.

Pam wrote:

To me it is a phenomenon  not seen before and I would like to know - not guess-  if other plants share this ability, and if so  which ones. 

Paleo Gardener wrote:
The tiny "root hairs" of plants allow soil creation during a plant's lifetime, since they grow out from the root briefly and then die once they harvest the nutrients from their spot.

Plants like willow and mint shoot out root hairs in water pretty easily, that's why I would guess they also would make soil in water. All we have to do is test the hypothesis to know!

Prairie grasses are very good at making soil, this is where the deep rich soil of the prairies came from - the growth and death of grass roots. 

This picture is hard to read but shows prairie plant root systems compared to Kentucky Bluegrass lawn roots; large-growing Tallgrasses like Indian Grass, Switchgrass and Big Bluestem have exceptionally large root systems:

H Ludi Tyler wrote:
Prairie grasses are very good at making soil, this is where the deep rich soil of the prairies came from - the growth and death of grass roots. 

This picture is hard to read but shows prairie plant root systems compared to Kentucky Bluegrass lawn roots; large-growing Tallgrasses like Indian Grass, Switchgrass and Big Bluestem have exceptionally large root systems:

Nice pic; got a link to a full size?

I believe that it came from this book:
http://www.il.nrcs.usda.gov/technical/plants/npg/

For an interesting read on root development, try this old (1929) book by John weaver:

http://www.soilandhealth.org/01aglibrary/010139fieldcroproots/010139toc.html
(many illustrations)

Dead root filaments, interesting.

By the way, here in Costa Rica mint is just not invasive. We are struggling to propagate it. Anyone know why?

My guess would be that Mint has a very low salt tolerance.