Comfrey Excavation

Curious how deep comfrey actually grows, so arranged for an excavator, and sacrificed a patch of circa 1980 AD comfrey.

The depest roots made it about 2 ft down. Coincidentally in this soil, 2 ft down was a hard line of orange sandstone. I was surprised to find the roots of the comfrey pried several inches into this mass I could barely break apart with my garden knife. I question now how deep they would grow in better soil?

Considering an experiment in which I fill a 50 gallon barrel with compost, and see if the comfrey grows to the bottom. I have no problems if someone beats me to it.

Comfrey can sink roots to around 8 feet.

Strangler fig tree roots are responsible for most of the destruction of 2500 year old temples in Thailand, Cambodia and India.
This same tree has been used to make root bridges for several thousand years too and some of the bridges span over 100 feet.

Oak tree roots can split granite, one of the hardest rocks found on the earth mother.

https://www.amazon.com/gp/product/0961584831/ref=oh_aui_search_detailpage?ie=UTF8&psc=1


This book really changed my mind about gardening.     Besides looking above the soil, beneath is a whole new world.

Mart Hale wrote:https://www.amazon.com/gp/product/0961584831/ref=oh_aui_search_detailpage?ie=UTF8&psc=1


This book really changed my mind about gardening.     Besides looking above the soil, beneath is a whole new world.

Totally agree. I have read that book. It was actually that book that prompted me to excavate comfrey. Kourik had very few examples I thought -not speaking badly of him, but as he said, not many examples around. Thanks for bringing it up!

Bryant RedHawk wrote:Comfrey can sink roots to around 8 feet.

Strangler fig tree roots are responsible for most of the destruction of 2500 year old temples in Thailand, Cambodia and India.
This same tree has been used to make root bridges for several thousand years too and some of the bridges span over 100 feet.

Oak tree roots can split granite, one of the hardest rocks found on the earth mother.

Fascinating about the strangler fig. Curious though what kind of soil those 8 ft roots were in. Was it sand?

Oak trees also have the ability to drill through subsurface bedrock by secreting an acidic chemical bath into cracks in the rock that disintegrates the rock and allows the roots to push through.  Generally, the roots will find a small fissure in the bedrock and as they push down into the crevice, the acids soften and widen the crack and give the root more and more space to grow.  Thus, over thousands of years, an oak forest will gradually disintegrate the bedrock below it, allowing roots to push ever deeper.

Some forms of fungi also dissolve rock and then make those minerals available to plant roots.  Thus, plants work in concert with the fungi to slowly dissolve those rocks/stones.  It takes thousands or even millions of years, but the result is deeper and finer soil.

Very nice, informative photos.

It would be nice to see year on year soil tests around comfrey roots at varying depths
Find a sweet spot for when to cull a patch.

Luke Simon wrote:Fascinating about the strangler fig. Curious though what kind of soil those 8 ft roots were in. Was it sand?

I measured those root depths in 1969 at my house in Sacramento Ca., the top soil was 100 feet deep, the house was located in an alluvial flood zone of the American River, soil type: Sandy, silty top soil.
I planted comfrey, alfalfa, daikon radish and buckwheat in a space 7' x 25', a transparent barrier of military grade Plexiglas was installed for observation during the experiment.
Results recorded: the comfrey roots went down 8 feet in two years (3.756' the first year), the alfalfa roots went down 7 feet in one year, the daikon radish grew to 3.17 feet in length in one growing season, the buckwheat roots only went down 3.55 feet (it's a shallower rooting plant apparently).
This soil had 29 thousand bacteria per cu. cm, 50 thousand mycelium per cu. cm, 22,419 nematodes per cu. inch and 14,226 amoeba and flagellates per cu. inch.
The soil was checked for these with a Zeiss Dark Field Microscope with a maximum power of 2500X, at the end of the trial this same microscope was fitted with abbe condenser, phase contrast and a polarization filter, gram stain was used for bacterial counts.
This was part of some of my studies done at the University of California, Davis (go Bruins).

Redhawk

Bryant RedHawk wrote:

Luke Simon wrote:Fascinating about the strangler fig. Curious though what kind of soil those 8 ft roots were in. Was it sand?

I measured those root depths in 1969 at my house in Sacramento Ca., the top soil was 100 feet deep, the house was located in an alluvial flood zone of the American River, soil type: Sandy, silty top soil.
I planted comfrey, alfalfa, daikon radish and buckwheat in a space 7' x 25', a transparent barrier of military grade Plexiglas was installed for observation during the experiment.
Results recorded: the comfrey roots went down 8 feet in two years (3.756' the first year), the alfalfa roots went down 7 feet in one year, the daikon radish grew to 3.17 feet in length in one growing season, the buckwheat roots only went down 3.55 feet (it's a shallower rooting plant apparently).
This soil had 29 thousand bacteria per cu. cm, 50 thousand mycelium per cu. cm, 22,419 nematodes per cu. inch and 14,226 amoeba and flagellates per cu. inch.
The soil was checked for these with a Zeiss Dark Field Microscope with a maximum power of 2500X, at the end of the trial this same microscope was fitted with abbe condenser, phase contrast and a polarization filter, gram stain was used for bacterial counts.
This was part of some of my studies done at the University of California, Davis (go Bruins).

Redhawk

Dang! Where was this study published? Or was it published at all? I’d love to spread the link around because this is fantastic, high quality research. Thanks so much for going to such lengths to gather that information Dr. Redhawk.

Interesting that comfrey can grow deeper in softer soil where it isn’t impeded by slate as was the case for my excavation. Thanks so much for enlightening me.

Here are some pictures of some roots penetrating about 15 feet of sand stone in western Colorado.  I thought it was cool enough to warrant a picture.

hau Luke, I don't believe the results were published since I was an undergraduate.
I do keep all my work note books though (my wife doesn't understand why I insist on keeping them, so I am putting them all onto memory sticks now).

Nice photos of what appear to be juniper roots Tom, Thanks for posting those here.
(did you notice that the portion in front of the root's exit points is being split away and will eventually fall off, leaving the roots completely exposed?)
(there has already been some shearing off, which is how those roots became visible)

Right on the money with juniper, the picture doesn't show it, but the roots enter the wet spot at the base of the cove.

Bryant RedHawk wrote:hau Luke, I don't believe the results were published since I was an undergraduate.
I do keep all my work note books though (my wife doesn't understand why I insist on keeping them, so I am putting them all onto memory sticks now).

Thank you for sharing that info here then. It's good stuff. I will link to this thread for reference and share it with others.Although if you have more info such as pictures, I would love to post about your study on my website.

Those are insane roots Tom. I have juniper plants, and now wonder how deep they go.