Soil Structure- is it important to add inorganic soil to balance out lots of added organic material?

I understand sand, silt, & clay make up the structure of soil (not including any organic material present).  Where I live in the Rocky Mountains my soil is only 2 parts - Sand and Rocks :)

Edit: the following question is specifically about the need to add inorganic materials (the silt, sand, clay, or other) to balance out any amount of added organic material.  I'm doing all I can to add organic material, but I'm adding so much I want to know if it's important to add back the inorganic parts that make up the structure of the soil.  After that I do have a question specifically about manure.  Thanks for replies, but I want to focus on these questions.

For years I've been spreading horse manure and free wood chips (mostly pine unfortunately because its available) all around my dry, dead, and sandy soil.  In the area where I garden I put a considerable amount (along with whatever compost and other organic materials I can collect) and have wondered is it important to also be adding the inorganic portions of the soil. Wikipedia has a chart that claims soil is only 5% organic material (although 50% is water/air) and in my case this percentage is closer to 50% (if we're still including water/air).  

Home Depot sells Top Soil that mostly resembles "fill dirt".  Would adding this be beneficial?

A current specific situation is I'm building some smaller hugelculture beds and need to source material to cover my dead branches and logs (also Pine, unfortunately, but some many years old).  Compost is readily available for purchase because I cannot accumulate enough at home.   Originally I was thinking about buying Steer Manure Compost Blend to fill the beds in hopes that the extra nitrogen would help speed up the decomposing of wood material.  But would Steer manure be hot for me to plant in by next June?-- If so I'll stay away and stick to compost. I do plan on adding Red Wine Cap spawn and other Mycorrhizal additives to jump start the process.  Would any amount of manure be a good or bad idea?

Is it important to add inorganic material if so far all I have to add to my beds are organic material?  Do people build hugelkulters with 100% compost/manure/organic materials and no actual structural soil!?!

Have you thought of going to a garden place that sells bulk soils and composts.
Also soil it elf is a complex material easily created, but you may look for some info either on the site or in Books specifically about creating soil.
Planting green manures adding  clay is all part of the process.
The clay helps with minerals.
Look at this web site
https://www.southwestvictorygardens.com/blog/how-to-improve-desert-soils

Dear hubby and I amde the soil for our raised beds buy gathering leaf mold aka hummus from under our oak trees.

That is something truly amazing if you happen to have lots of trees.

If not, I would recommend starting to compost anything you might have access to such as leaves, coffee grounds, veggie scapes, chicken bedding, etc.

It will soon be time for the leaves to start falling and many folks will have lots of leaves to dispose of.  Gather up those bags of leaves and fill those hugelkulture beds with them.

Ask at the local coffee shop if you can have their coffee ground as that is another item to fill those beds.

Grass clipping, veggie scrapes, shredded paper, and cardboard also work.

To answer this question: "When using compost in large amounts, is it important to also add in the inorganic parts of soil?" I would say it is best to add organic materials unless you need to use the inorganic material as a filler.

Best wishes for great hugelkulture beds!

Wood chips are useful, but tricky.

In a damp climate with a long season above freezing, they break down quite quickly.

In a dry climate with a short growing season and long below-zero winter, they hang around for years. I have taken to soaking them (for a month or more) in a mix of compost tea, urine, municipal compost, garden/forest soil, and biochar before applying. That way they're partially broken down not a drag on the nutrients for my plants.

Thanks for the replies.  I've been doing all what you suggested and yes, in my dry climate it is taking forever.  I try to carefully word my posts to focus on my questions at hand.  I may need to edit my original post to focus on my question about if it's important to add inorganic materials to balance the organic materials.  But regarding your other suggestions:

John C Daley wrote:Have you thought of going to a garden place that sells bulk soils and composts....
Planting green manures adding  clay is all part of the process.
The clay helps with minerals.
Look at this web site...

I don't have a pickup truck or trailer to haul bulk soil.  I hate buying bagged compost but the clearance soil makes this more affordable anyhow.  I have tons of green manure plants currently growing, it's an uphill battle with how dry my climate is.  Do others add clay for structure in their soil?  As I mentioned my soil is 95% sand with almost no clay or silt.  I don't think I have a mineral deficiency because my soil is the mountain particles of which it sits (the sand is crushed rocks--I live in the rocky mountains).

Anne Miller wrote:...gathering leaf mold aka hummus from under our oak trees....many folks will have lots of leaves to dispose of...Gather up those bags of leaves and fill those hugelkulture beds with them.

If not, I would recommend starting to compost anything you might have access to such as leaves, coffee grounds, veggie scapes, chicken bedding, etc.

To answer this question: "When using compost in large amounts, is it important to also add in the inorganic parts of soil?" I would say it is best to add organic materials unless you need to use the inorganic material as a filler.

Best wishes for great hugelkulture beds!

Hi, all my trees are evergreen, no leaves, although I've planted 20 decidious trees so hopefully in a few years they'll start giving me leaves.  Yes, I've made it a point to gather leaves from other neighborhoods.  Last year I posted an ad on craigslist and was overwhelmed.  They didn't break down as much as I had hoped but I'm happy to have anything.  Yes, I collect all the coffee grounds from local starbucks, and I compost everything I have, including the kobashi method I recently started.  I also shred all my cardboard boxes.

Regarding your last sentence, this is why I posted.  Is it important to have these inorganic elements?

Douglas Alpenstock wrote:...In a dry climate with a short growing season and long below-zero winter, [wood chips] hang around for years. I have taken to soaking them (for a month or more) in a mix of compost tea, urine, municipal compost, garden/forest soil, and biochar before applying. That way they're partially broken down not a drag on the nutrients for my plants.

Yes, I'm experiencing this issue.  I am doing all you suggest and staying patient.  I want to know if adding inorganic particles may help.

S Marshall said, "  I want to know if adding inorganic particles may help.

I asked what is inorganic materials in the soil? Mr Google said:

Soils usually contain inorganic material of three sizes: sand, which ranges in diameter from 0.2 to 2 millimetres; silt, between 0.02 and 0.002 millimetres in diameter; and clay, which is less than 0.002 millimetres. Most soils have some of each. Soils with a large proportion of each component are called loams.

Does the soil need sand, silt and clay?

Probably if someone has these readily available to add to compost though I don't feel it is entirely necessary to grow plants.

I have grown beautiful plants in straight finished compost.

This might help you or others:

https://permies.com/t/63914/Soil#549590

Hi Anne,
Thanks for that link!  I've read parts of Redhawks thread before and each time it's a welcome reminder!  My soil is 95% sand.  That's good to know you feel confident growing in 100% compost.  I've been reading about the benefits of loam soil which as you quotes has large proportions of each sand, silt, and clay.

Because 100% organic material (compost, manure, decaying wood chips, leaves, kitchen scraps...) contains no sand, silt, or clay, I was wondering if people here knew it would therefore be important to add back into soil you have greatly amended with only organic material.

Especially if these inorganic materials are important to soil structure.  I've read a lot about the importance of good soil structure (loam) although I'm unclear exactly what is implied. For instance, is this needed for hugelkultur beds or else it will fall down or erode quicker?  

My head is spinning a bit as I feel like I'm asking a question that makes sense to me but maybe I'm not expressing it correctly?

I have hard packed clay soil. I always have a big compost pile going to amend all my beds. Usually 12' x 12' and I keep adding to it all year so it is usually  3-4' deep or thereabouts. All the leftover vegie plants, weeds, grasses and lots and lots of leaves. About 5 years ago I got super busy, too busy to load up my wheelbarrow and haul it to all the beds around my yard. So I took some cinder blocks and surrounded it with 3 courses and just planted into it that year. All the vegies grew super well until they all got bigger and fell over and collapsed. The soil wasn't thick enough or dense enough to give their roots anything to hold onto so they couldn't hold themselves up. I tried to stake a lot of the peppers and tomatoes but the stakes couldn't even stay up. The inorganic matter is the 'concrete' the plants need to hold onto. Hope this answers your question.

And everyone here gave you lots of great advice.

Thanks, Debbie.  This is super helpful.  It does seem the structure of inorganic materials are important.  It's just odd others say they plant in pure compost all the time and it's fine --  maybe they aren't realizing their pure compost was mixed into their soil?

I'm sensing that I'm sounded a bit difficult.  In fact it's been a hard week where I'm feeling like nobody is hearing me correctly so I'm being extra deliberate in an attempt to get the response that maybe I want to hear.

Since this is the soil forum I was hoping someone would clearly chime in and say, "Yes, you need to amend your soil with these inorganic particles that make up loam if it is not present in your mix".  But I have not seen that anywhere.  What I have seen is much discussion of how loam soil is good.  And much discussion about huge compost piles with as much organic materials as one can collect.   So, unless I'm missing something, no one seems to be making the connections between needing BOTH loam soil MIXED with compost.  And, if that is a correct, I am curious about what percentage the organic material should be.  I'm asking this because I'm about to create hugelkulters with pure compost and want to know how much silt, clay, & sand I should add.  I think I'll start a thread over there to ask as well.

Perhaps the amount of organic material is a big range, like anywhere from 10%-40% organic material.  But it could as well be 10%-90% for all I know.  Wiki has that chart saying 10% organic (it's listed as 5% because they have water and air taking 50%).

Yes, I'm overthinking this.

Clay is good for moisture retention. If you have plenty of year-round moisture, it might not be an issue for you. But if your plants suffer during droughts, adding some clay might help with that. I've grown indoor tomatoes in 100% compost and they were fine, but as houseplants they had a regular watering schedule.

Jennifer Pearson wrote:Clay is good for moisture retention....

Great advice! I've heard clay is useful for building ponds, and I believe elsewhere about holding water.  So here's an example of my needing to add soil to my sandy soil.  The reason I never pursued this in the past is because where the heck does someone buy clay?!
Although it just occurred to me I use Turface in my container gardens and it is comprised of "Heat Treated Montmorillonite Clay Mineral"!  So if I can't find bags of clay would I use this instead?

Does anyone know what silt would be used for?  And where to get it?

"Clay on sand is money in the hand, sand on clay will never pay." (an old farmer's saying)... so it sounds like you are in a workable situation. Its usually good to look to the law of the minimum, or to your limiting factor for healthy plant growth. In your case it sounds like water and nutrient retention are your limiting factors. So clay and organic matter (compost is an ideal form of this) are going to be of greatest benefit to you. In my case on rocky clay, I do mix in some sharp river sand with compost when making raised bed to aid soil aeration and water infiltration. Over the long term worms and other soil life will mix up layers, but this does take time, so in cases where I have heavy equipment to do so, or if its just a small bed, I mix it first

S. Marshall wrote:

Douglas Alpenstock wrote:...In a dry climate with a short growing season and long below-zero winter, [wood chips] hang around for years. I have taken to soaking them (for a month or more) in a mix of compost tea, urine, municipal compost, garden/forest soil, and biochar before applying. That way they're partially broken down not a drag on the nutrients for my plants.

Yes, I'm experiencing this issue.  I am doing all you suggest and staying patient.  I want to know if adding inorganic particles may help.

We all want to help you find a solution. I find it hard to comment in a specific way without holding the soil in my hand, smelling it, seeing if it clumps when moist, seeing how it drains, seeing how it reacts to water when dry, and seeing how different plants react to it -- all those intangible things.

I'm growing in a sand hill now, and I am amazed at how enormous volumes of organic matter disappear without a trace.
I don't think you can do any harm by adding commercial soil and steer manure. The more the merrier.  The inorganic components in the commercial soil may do some good for the overall soil matrix.

The idea of adding clay for the micronutrients (and moisture retention?) is intriguing, but I'm not sure. I know that adding fine sand to a clay based soil can result in a sort of concrete. But what about adding clay to a fine sandy soil? I have sources for free clay, and I'm inclined to test it out.  

EDIT: I see I missed a number of very helpful posts while I was mulling over my response.

Ben Zumeta wrote:"Clay on sand is money in the hand, sand on clay will never pay." (an old farmer's saying)... so it sounds like you are in a workable situation. Its usually good to look to the law of the minimum, or to your limiting factor for healthy plant growth. In your case it sounds like water and nutrient retention are your limiting factors. So clay and organic matter (compost is an ideal form of this) are going to be of greatest benefit to you.

Thanks. Ben! I hadn't heard that one before! It may be directly applicable to my situation as well.

Clay is naturally deposited anywhere moving water carrying eroded soil comes to a stop, allowing the clay to settle out. This is an under-appreciated reason why the key-point in a valley is often the most suitable for ponds, as clay has been naturally depositing there.

S. Marshall, I think you are getting stuck on the "adding inorganic material back" statement... You already have the inorganic material/soil, and you are adding organic material/compost TO this soil.

To turn your "sand" into "sandy loam" you might aim for 5%-10% organic matter, and for building your hugelculture, the woody materials count towards that, and mixing a subsoil with topsoil (all from that excavation) would result in the whole hugel becoming a rich soil.
Since it sounds like your "topsoil" is just all sandy, mixing compost along with it to build the hugel seems logical. You'd jumpstart a community of microbes, and have something to plant into.

If you just filled the hugel with compost, it would break down quickly, and as Debbie pointed out, there's no ballast to hold up the plants, or hold the compost from eroding away; it might drain poorly, and there's fewer minerals.

Thanks everyone.  I feel good about my concern that building beds with compost.  It's interesting I haven't found info regarding this concern and typically see it encouraged.  All your replies in this discussion have been very helpful.

Does anyone know where to buy clay and silt amendments?  My soil is 99% sand and I would like to make it loam before adding compost to make my beds.  I mentioned earlier I have "Turface" which is the material used in baseball in-fields and have been using it for years in my container gardens because each piece is over 1/8" and doesn't add to water retention issues.  It is made of ""Heat Treated Montmorillonite Clay Mineral" and holds its weight in water.  But not in containers is having this pelletized form not as good as clay one might purchase elsewhere intended for soil?  Where would one buy clay to build a pond?

Ben mentioned the farmer's saying, "Clay on sand is money in the hand, sand on clay will never pay.".  What climate is that applicable?  If it's farmland in an area with decent rainfall and humidity I'm wondering if this wouldn't be appropriate for very dry Colorado.  If I add clay on top of my sand for the purpose of retaining water I fear it would only absorb the little water we get and then allow it to evaporate, no?  Our rain showers are usually 1/10" and though it appears things get wet it only soaks in 1/4".  

If I'm right, would it make more sense for my layer of clay to be mixed into my sand?

Kenneth Elwell wrote:... You already have the inorganic material/soil, and you are adding organic material/compost TO this soil....
..Since it sounds like your "topsoil" is just all sandy, mixing compost along with it to build the hugel seems logical.

To paint a picture, my soil is completely sandy down to the bedrock.  It sounds like you think only my top soil is sand and if I used an excavator for this project I would be able to pull up deeper rich soil.  I have no deeper rich soil!  

If I used any excavated sand it would still lack the clay and silt needed to make loam.  I guess sand & compost is better than compost alone, but I believe I'm convinced to at least add clay to help.  Where would I get silt?

I also wasn't planning on using an excavator because I can't afford it.  I'm afraid I'm simply building this on top of my soil and hence why I need to purchase this additional soil.  

Hi everyone.  I just learned something else one this website - https://www.smilinggardener.com/lessons/how-to-improve-clay-soil-and-sandy-soil/

I believe they are simply pushing compost but it's all worth considering.  However, the greatest takeaway was in something I already have learned about water retention (hinted at early when I mentioned my container gardening).  A user named Al (aka Tapla) on Houzz container gardening forum (formally Gardenweb) is nothing short of a guru when it comes to container gardening, and it's all about the soil medium.  Here is a link if you want to learn everything you would ever need to know, his thesis is "Water Retention". https://www.houzz.com/discussions/6167237/container-soils-water-movement-and-retention-8-26-21
He first stated this thesis probably over a decade ago but it's so important to understand.  He updates it all the time.  In short, no particles in a container should be smaller than 1/8" so that there is no water retention issues and there is plenty of air between each particle (very much simplifying).  He also busts the myth about placing rocks on the bottom of containers in order to help drainage.  This does the exact opposite by raising the perched water table.

Back to my first link.  They mention how golf courses lay down a layer of gravel before putting in the topsoil for the grass, and the purpose of this is to provide more moisture to the short grass roots.  What they are doing is creating a perched water table!  It won't be 100% like it would be in a container because it is still effectively tied to the earth below, but it the gravel is dense enough I can see it would certainly slow.  And if this is true about golf courses it must work!

I know many of you don't live in tremendously dry areas.  It's been recommended to me in the past to use my rocks as mulch, but I'm wondering if using rocks under beds would help slow the water from draining away?

I suggest an experiment:

Fill one pot with rocks, another with your sand, maybe one with potting soil and another with compost. You could add one of clay or silt if its available conveniently (or it could give you an excuse to go hang out by or in some water)*.

Use a watering can to pour measured amounts through each medium and see which on holds the most water before runoff. I have a hypothesis how this will go, but its always better to observe for yourself.

*again anywhere moving water comes to a stop will have sediment particles of descending size as the water slows down, including silt and clay layers as it really stops. Go to a river confluence and observe how the gradient from boulders to gravel to sand, silt and then clay. Water carries exponentially more and larger sediment as it moves faster and with larger volume. This creates a sedimentation gradient where it slows down, like river bends, confluences, mouths and lake edges.

You could also buy some 50lb bags of azomite clay for not too much and experiment with that. It will only add minerals and water holding capacity. Also, both clay and true compost are colloids, which are extremely fine particles that have immensely higher surface area and cation exchange capacity than sand, thus holding much more water and nutrients much longer.

I concur with the compost pushers, as adding organic matter, which compost is an ideal form of, helps virtually all soils. This is why virtually all forms of terrestrial ecosystem succession build organic matter over time until a catastrophic disturbance.

I also recommend reading the Permaculture Designer’s Manual, particularly sections on deserts and atoll islands.

On transforming any soil:

Are you familiar with any of the "greening the desert" work being done?   I dont have any direct answer for you as far as improving sand based soil structures.   But research in that specific area might give you an overview of strategies to look at to see if any apply to your situation or present ideas you haven't come across yet in this adventure?  

I'll also add that one of my first thoughts on "is it important" was "depends on what you are trying to grow."  

One source of clay is some types of Kitty Litter. If you can create a hot compost, you might get it for free, inoculated with cat pee/poop, but I wouldn't want to use that without being sure you'd killed any of the potentially nasty stuff. It seems crazy that so much of it goes to the landfill.

The problem with sandy soil is that it doesn't hold moisture. Have you read the biochar forum here on permies? Biochar helps to hold moisture in soil, and helps hold on to the valuable microbes.

Have you read/watched books and videos by David (the) Good?  for example: https://permies.com/wiki/56810/Grow-Die-Good-Guide-Survival
He has done some experiments dealing with really sandy soil, so he might have some insights for you. That link is to an older book. I know I watched a video of a much more recent attempt at working with sandy soil where I think biochar was part of the solution.

If you do decide to incorporate clay, I believe I read/watched somewhere that just like the biochar, mixing it into a compost pile that you're building, and then using the results was a recommended approach, but I can't remember where I read that or whether they included a rational. I do recall Dr. Redhawk specifically saying that adding soil to compost was a good thing. I think that was to add starter microbes though, and pure sand or pure clay many not have many microbes. However, worms carry lots of microbes in their guts. They won't be in a really hot compost, but they move in when it cools.

Sandy soil is tough to deal with - hopefully you'll find some things that work for you.